From patchwork Wed Oct 16 20:27:44 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Samuel Holland X-Patchwork-Id: 836000 Received: from mail-pj1-f54.google.com (mail-pj1-f54.google.com [209.85.216.54]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2D92C21644E for ; Wed, 16 Oct 2024 20:28:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.54 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729110504; cv=none; b=FIbiTwlOurQvmndmwFNxoXCWaK7B0MtKVZjPcGlfKtPKkLUT790V1l6vVwtkTrqxwcY3qnJQbJZbrGsga3ixVF4SzA++nms5+1f9fYad9reCGkTrVTO2FOLllaTYbQQibCOOWwOrKjAc7PtqYbigJto39uwy+jK5e5j3sgeP4IM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729110504; c=relaxed/simple; bh=G3tcHs0vugRLIs9AZLkTyVmXxoSZrPQ98Ip0I2VATc4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ijFmwOOAr5RQ4m0UTLYP+Vmwdmo2kD73tRSZuhRqgWuQ7nyGAEQwMpifLxdQoaBy6mQX+0/n6A+p8l+Y3nXBrYVOSP5crQN/bNLaXQUklnd8Wt9MB1u+PwWOxnOVO88gEM5HqctVA1IhIdQJ/0ljgHw6DrzXH0AjJE9bTWu/acY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=sifive.com; spf=pass smtp.mailfrom=sifive.com; dkim=pass (2048-bit key) header.d=sifive.com header.i=@sifive.com header.b=fE6R9JoT; arc=none smtp.client-ip=209.85.216.54 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=sifive.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sifive.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=sifive.com header.i=@sifive.com header.b="fE6R9JoT" Received: by mail-pj1-f54.google.com with SMTP id 98e67ed59e1d1-2e2ad9825a7so172337a91.0 for ; Wed, 16 Oct 2024 13:28:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sifive.com; s=google; t=1729110502; x=1729715302; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=q8L9RcsXGBuOOIJkGyl0uzoPHSEP08/B/TxdDRrdDog=; b=fE6R9JoToN9iNBYxzX4tzIDJXRub40c4vCs9CZsWMcxBpadpIlwl/zgmxj+N5Lg6ew kc267vpfGbIfj1mTF0EdmWn1HC+Go/jhxDDTCk7PAt0TewqN51Jt16jmxX8y/tcd05Ru 2tWyAGWR7OjbZiDPQVg70IDXJFBj/RhJPcqohqFu4Iksahol8lAPDo8s3TqcCjXAY2x6 uKawWcg2TjwhxWdH5SWKfwXOLj9NtuPvI8RNf67Ow3c3S8ubr3MtR6HP6rODnBV7/aHM ZZK9msk3HrnFy0I51Qms6TAcHazIzg5ytNrnALrjBq3VyT+bp7m2Qr3GFtFxQEAj8DbY BJkw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1729110502; x=1729715302; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=q8L9RcsXGBuOOIJkGyl0uzoPHSEP08/B/TxdDRrdDog=; b=ZeZa/THcvtzpvIf+z/Amk7QGsEnTlUUbNTLL7tWoKajN0BtVKQTBVIpFmx33rVzQUB W7tiSCaIIejruUBCaDpMjiaak447T16gudW/1rjgcBcciyIXHAFukEIe9stdL/P+yFV3 RkxBoyFzdGd8u/s0F01jsCQ02HAJzSkQA2rhHC5FoRm1CT4+C7sQLlJ96ikZtthIMMu6 O4kDI+se6H09b2exNTto3jlLuXnWXgnY0j464smDr7FvFFfsfzrRV9AB67ol7WZWpiA4 IPm2iTWvdSDlCvf/ydX9c4ljUJdOIunCvYlAbGqehM3IYxOrMUemqh4kF+7Bk898pfCN VvyA== X-Forwarded-Encrypted: i=1; AJvYcCXwpScLhrL8YR60I6iEd5eJSgNLSTjj/0SuLZCeIKPLCbEUiI0HmNrXLsvalVTKssgPpArrIY6ONwVKgGn9lwM=@vger.kernel.org X-Gm-Message-State: AOJu0YyzAPSTOKWyUKn788+20uSXf65q30Y72yOTu3x1Y/y2FmgNFQQq 6Km5HdpIH4dy7lNIEuYhwnJAFDCpggyqLxezbDh2odqA2Wzz198O6UPjr9F6aVE= X-Google-Smtp-Source: AGHT+IEcrRzQueyWfGvwY23TG0nBCtrzNyg/XChtvSqTPLeH3iuBVoZX2ptDYNex9tUfXpxWrJVkCg== X-Received: by 2002:a17:90b:2313:b0:2e2:cf5c:8ee3 with SMTP id 98e67ed59e1d1-2e3ab7fe655mr6587578a91.10.1729110502579; Wed, 16 Oct 2024 13:28:22 -0700 (PDT) Received: from sw06.internal.sifive.com ([4.53.31.132]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2e3e08f8f89sm228613a91.38.2024.10.16.13.28.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Oct 2024 13:28:22 -0700 (PDT) From: Samuel Holland To: Palmer Dabbelt , linux-riscv@lists.infradead.org Cc: Catalin Marinas , Atish Patra , linux-kselftest@vger.kernel.org, Rob Herring , "Kirill A . Shutemov" , Shuah Khan , devicetree@vger.kernel.org, Anup Patel , linux-kernel@vger.kernel.org, Jonathan Corbet , kvm-riscv@lists.infradead.org, Conor Dooley , kasan-dev@googlegroups.com, linux-doc@vger.kernel.org, Evgenii Stepanov , Charlie Jenkins , Krzysztof Kozlowski , Samuel Holland Subject: [PATCH v5 03/10] riscv: Add CSR definitions for pointer masking Date: Wed, 16 Oct 2024 13:27:44 -0700 Message-ID: <20241016202814.4061541-4-samuel.holland@sifive.com> X-Mailer: git-send-email 2.45.1 In-Reply-To: <20241016202814.4061541-1-samuel.holland@sifive.com> References: <20241016202814.4061541-1-samuel.holland@sifive.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Pointer masking is controlled via a two-bit PMM field, which appears in various CSRs depending on which extensions are implemented. Smmpm adds the field to mseccfg; Smnpm adds the field to menvcfg; Ssnpm adds the field to senvcfg. If the H extension is implemented, Ssnpm also defines henvcfg.PMM and hstatus.HUPMM. Reviewed-by: Charlie Jenkins Signed-off-by: Samuel Holland --- (no changes since v3) Changes in v3: - Use shifts instead of large numbers in ENVCFG_PMM* macro definitions Changes in v2: - Use the correct name for the hstatus.HUPMM field arch/riscv/include/asm/csr.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h index 25966995da04..fe5d4eb9adea 100644 --- a/arch/riscv/include/asm/csr.h +++ b/arch/riscv/include/asm/csr.h @@ -119,6 +119,10 @@ /* HSTATUS flags */ #ifdef CONFIG_64BIT +#define HSTATUS_HUPMM _AC(0x3000000000000, UL) +#define HSTATUS_HUPMM_PMLEN_0 _AC(0x0000000000000, UL) +#define HSTATUS_HUPMM_PMLEN_7 _AC(0x2000000000000, UL) +#define HSTATUS_HUPMM_PMLEN_16 _AC(0x3000000000000, UL) #define HSTATUS_VSXL _AC(0x300000000, UL) #define HSTATUS_VSXL_SHIFT 32 #endif @@ -195,6 +199,10 @@ /* xENVCFG flags */ #define ENVCFG_STCE (_AC(1, ULL) << 63) #define ENVCFG_PBMTE (_AC(1, ULL) << 62) +#define ENVCFG_PMM (_AC(0x3, ULL) << 32) +#define ENVCFG_PMM_PMLEN_0 (_AC(0x0, ULL) << 32) +#define ENVCFG_PMM_PMLEN_7 (_AC(0x2, ULL) << 32) +#define ENVCFG_PMM_PMLEN_16 (_AC(0x3, ULL) << 32) #define ENVCFG_CBZE (_AC(1, UL) << 7) #define ENVCFG_CBCFE (_AC(1, UL) << 6) #define ENVCFG_CBIE_SHIFT 4 @@ -216,6 +224,12 @@ #define SMSTATEEN0_SSTATEEN0_SHIFT 63 #define SMSTATEEN0_SSTATEEN0 (_ULL(1) << SMSTATEEN0_SSTATEEN0_SHIFT) +/* mseccfg bits */ +#define MSECCFG_PMM ENVCFG_PMM +#define MSECCFG_PMM_PMLEN_0 ENVCFG_PMM_PMLEN_0 +#define MSECCFG_PMM_PMLEN_7 ENVCFG_PMM_PMLEN_7 +#define MSECCFG_PMM_PMLEN_16 ENVCFG_PMM_PMLEN_16 + /* symbolic CSR names: */ #define CSR_CYCLE 0xc00 #define CSR_TIME 0xc01 @@ -382,6 +396,8 @@ #define CSR_MIP 0x344 #define CSR_PMPCFG0 0x3a0 #define CSR_PMPADDR0 0x3b0 +#define CSR_MSECCFG 0x747 +#define CSR_MSECCFGH 0x757 #define CSR_MVENDORID 0xf11 #define CSR_MARCHID 0xf12 #define CSR_MIMPID 0xf13 From patchwork Wed Oct 16 20:27:46 2024 Content-Type: text/plain; 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Shutemov" , Shuah Khan , devicetree@vger.kernel.org, Anup Patel , linux-kernel@vger.kernel.org, Jonathan Corbet , kvm-riscv@lists.infradead.org, Conor Dooley , kasan-dev@googlegroups.com, linux-doc@vger.kernel.org, Evgenii Stepanov , Charlie Jenkins , Krzysztof Kozlowski , Samuel Holland Subject: [PATCH v5 05/10] riscv: Add support for the tagged address ABI Date: Wed, 16 Oct 2024 13:27:46 -0700 Message-ID: <20241016202814.4061541-6-samuel.holland@sifive.com> X-Mailer: git-send-email 2.45.1 In-Reply-To: <20241016202814.4061541-1-samuel.holland@sifive.com> References: <20241016202814.4061541-1-samuel.holland@sifive.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 When pointer masking is enabled for userspace, the kernel can accept tagged pointers as arguments to some system calls. Allow this by untagging the pointers in access_ok() and the uaccess routines. The uaccess routines must peform untagging in software because U-mode and S-mode have entirely separate pointer masking configurations. In fact, hardware may not even implement pointer masking for S-mode. Since the number of tag bits is variable, untagged_addr_remote() needs to know what PMLEN to use for the remote mm. Therefore, the pointer masking mode must be the same for all threads sharing an mm. Enforce this with a lock flag in the mm context, as x86 does for LAM. The flag gets reset in init_new_context() during fork(), as the new mm is no longer multithreaded. Reviewed-by: Charlie Jenkins Tested-by: Charlie Jenkins Signed-off-by: Samuel Holland --- Changes in v5: - Document that the RISC-V tagged address ABI is the same as AArch64 Changes in v4: - Combine __untagged_addr() and __untagged_addr_remote() Changes in v3: - Use IS_ENABLED instead of #ifdef when possible - Implement mm_untag_mask() - Remove pmlen from struct thread_info (now only in mm_context_t) Changes in v2: - Implement untagged_addr_remote() - Restrict PMLEN changes once a process is multithreaded Documentation/arch/riscv/uabi.rst | 4 ++ arch/riscv/include/asm/mmu.h | 7 +++ arch/riscv/include/asm/mmu_context.h | 13 +++++ arch/riscv/include/asm/uaccess.h | 43 ++++++++++++++-- arch/riscv/kernel/process.c | 73 ++++++++++++++++++++++++++-- 5 files changed, 130 insertions(+), 10 deletions(-) diff --git a/Documentation/arch/riscv/uabi.rst b/Documentation/arch/riscv/uabi.rst index ddb8359a46ed..243e40062e34 100644 --- a/Documentation/arch/riscv/uabi.rst +++ b/Documentation/arch/riscv/uabi.rst @@ -80,3 +80,7 @@ number of mask/tag bits needed by the application. ``PR_PMLEN`` is interpreted as a lower bound; if the kernel is unable to satisfy the request, the ``PR_SET_TAGGED_ADDR_CTRL`` operation will fail. The actual number of tag bits is returned in ``PR_PMLEN`` by the ``PR_GET_TAGGED_ADDR_CTRL`` operation. + +Additionally, when pointer masking is enabled (``PR_PMLEN`` is greater than 0), +a tagged address ABI is supported, with the same interface and behavior as +documented for AArch64 (Documentation/arch/arm64/tagged-address-abi.rst). diff --git a/arch/riscv/include/asm/mmu.h b/arch/riscv/include/asm/mmu.h index c9e03e9da3dc..1cc90465d75b 100644 --- a/arch/riscv/include/asm/mmu.h +++ b/arch/riscv/include/asm/mmu.h @@ -25,9 +25,16 @@ typedef struct { #ifdef CONFIG_BINFMT_ELF_FDPIC unsigned long exec_fdpic_loadmap; unsigned long interp_fdpic_loadmap; +#endif + unsigned long flags; +#ifdef CONFIG_RISCV_ISA_SUPM + u8 pmlen; #endif } mm_context_t; +/* Lock the pointer masking mode because this mm is multithreaded */ +#define MM_CONTEXT_LOCK_PMLEN 0 + #define cntx2asid(cntx) ((cntx) & SATP_ASID_MASK) #define cntx2version(cntx) ((cntx) & ~SATP_ASID_MASK) diff --git a/arch/riscv/include/asm/mmu_context.h b/arch/riscv/include/asm/mmu_context.h index 7030837adc1a..8c4bc49a3a0f 100644 --- a/arch/riscv/include/asm/mmu_context.h +++ b/arch/riscv/include/asm/mmu_context.h @@ -20,6 +20,9 @@ void switch_mm(struct mm_struct *prev, struct mm_struct *next, static inline void activate_mm(struct mm_struct *prev, struct mm_struct *next) { +#ifdef CONFIG_RISCV_ISA_SUPM + next->context.pmlen = 0; +#endif switch_mm(prev, next, NULL); } @@ -30,11 +33,21 @@ static inline int init_new_context(struct task_struct *tsk, #ifdef CONFIG_MMU atomic_long_set(&mm->context.id, 0); #endif + if (IS_ENABLED(CONFIG_RISCV_ISA_SUPM)) + clear_bit(MM_CONTEXT_LOCK_PMLEN, &mm->context.flags); return 0; } DECLARE_STATIC_KEY_FALSE(use_asid_allocator); +#ifdef CONFIG_RISCV_ISA_SUPM +#define mm_untag_mask mm_untag_mask +static inline unsigned long mm_untag_mask(struct mm_struct *mm) +{ + return -1UL >> mm->context.pmlen; +} +#endif + #include #endif /* _ASM_RISCV_MMU_CONTEXT_H */ diff --git a/arch/riscv/include/asm/uaccess.h b/arch/riscv/include/asm/uaccess.h index 72ec1d9bd3f3..fee56b0c8058 100644 --- a/arch/riscv/include/asm/uaccess.h +++ b/arch/riscv/include/asm/uaccess.h @@ -9,8 +9,41 @@ #define _ASM_RISCV_UACCESS_H #include +#include #include /* for TASK_SIZE */ +#ifdef CONFIG_RISCV_ISA_SUPM +static inline unsigned long __untagged_addr_remote(struct mm_struct *mm, unsigned long addr) +{ + if (riscv_has_extension_unlikely(RISCV_ISA_EXT_SUPM)) { + u8 pmlen = mm->context.pmlen; + + /* Virtual addresses are sign-extended; physical addresses are zero-extended. */ + if (IS_ENABLED(CONFIG_MMU)) + return (long)(addr << pmlen) >> pmlen; + else + return (addr << pmlen) >> pmlen; + } + + return addr; +} + +#define untagged_addr(addr) ({ \ + unsigned long __addr = (__force unsigned long)(addr); \ + (__force __typeof__(addr))__untagged_addr_remote(current->mm, __addr); \ +}) + +#define untagged_addr_remote(mm, addr) ({ \ + unsigned long __addr = (__force unsigned long)(addr); \ + mmap_assert_locked(mm); \ + (__force __typeof__(addr))__untagged_addr_remote(mm, __addr); \ +}) + +#define access_ok(addr, size) likely(__access_ok(untagged_addr(addr), size)) +#else +#define untagged_addr(addr) (addr) +#endif + /* * User space memory access functions */ @@ -130,7 +163,7 @@ do { \ */ #define __get_user(x, ptr) \ ({ \ - const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \ + const __typeof__(*(ptr)) __user *__gu_ptr = untagged_addr(ptr); \ long __gu_err = 0; \ \ __chk_user_ptr(__gu_ptr); \ @@ -246,7 +279,7 @@ do { \ */ #define __put_user(x, ptr) \ ({ \ - __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \ + __typeof__(*(ptr)) __user *__gu_ptr = untagged_addr(ptr); \ __typeof__(*__gu_ptr) __val = (x); \ long __pu_err = 0; \ \ @@ -293,13 +326,13 @@ unsigned long __must_check __asm_copy_from_user(void *to, static inline unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n) { - return __asm_copy_from_user(to, from, n); + return __asm_copy_from_user(to, untagged_addr(from), n); } static inline unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n) { - return __asm_copy_to_user(to, from, n); + return __asm_copy_to_user(untagged_addr(to), from, n); } extern long strncpy_from_user(char *dest, const char __user *src, long count); @@ -314,7 +347,7 @@ unsigned long __must_check clear_user(void __user *to, unsigned long n) { might_fault(); return access_ok(to, n) ? - __clear_user(to, n) : n; + __clear_user(untagged_addr(to), n) : n; } #define __get_kernel_nofault(dst, src, type, err_label) \ diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c index 200d2ed64dfe..58b6482c2bf6 100644 --- a/arch/riscv/kernel/process.c +++ b/arch/riscv/kernel/process.c @@ -213,6 +213,10 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) unsigned long tls = args->tls; struct pt_regs *childregs = task_pt_regs(p); + /* Ensure all threads in this mm have the same pointer masking mode. */ + if (IS_ENABLED(CONFIG_RISCV_ISA_SUPM) && p->mm && (clone_flags & CLONE_VM)) + set_bit(MM_CONTEXT_LOCK_PMLEN, &p->mm->context.flags); + memset(&p->thread.s, 0, sizeof(p->thread.s)); /* p->thread holds context to be restored by __switch_to() */ @@ -258,10 +262,16 @@ enum { static bool have_user_pmlen_7; static bool have_user_pmlen_16; +/* + * Control the relaxed ABI allowing tagged user addresses into the kernel. + */ +static unsigned int tagged_addr_disabled; + long set_tagged_addr_ctrl(struct task_struct *task, unsigned long arg) { - unsigned long valid_mask = PR_PMLEN_MASK; + unsigned long valid_mask = PR_PMLEN_MASK | PR_TAGGED_ADDR_ENABLE; struct thread_info *ti = task_thread_info(task); + struct mm_struct *mm = task->mm; unsigned long pmm; u8 pmlen; @@ -276,16 +286,41 @@ long set_tagged_addr_ctrl(struct task_struct *task, unsigned long arg) * in case choosing a larger PMLEN has a performance impact. */ pmlen = FIELD_GET(PR_PMLEN_MASK, arg); - if (pmlen == PMLEN_0) + if (pmlen == PMLEN_0) { pmm = ENVCFG_PMM_PMLEN_0; - else if (pmlen <= PMLEN_7 && have_user_pmlen_7) + } else if (pmlen <= PMLEN_7 && have_user_pmlen_7) { + pmlen = PMLEN_7; pmm = ENVCFG_PMM_PMLEN_7; - else if (pmlen <= PMLEN_16 && have_user_pmlen_16) + } else if (pmlen <= PMLEN_16 && have_user_pmlen_16) { + pmlen = PMLEN_16; pmm = ENVCFG_PMM_PMLEN_16; - else + } else { return -EINVAL; + } + + /* + * Do not allow the enabling of the tagged address ABI if globally + * disabled via sysctl abi.tagged_addr_disabled, if pointer masking + * is disabled for userspace. + */ + if (arg & PR_TAGGED_ADDR_ENABLE && (tagged_addr_disabled || !pmlen)) + return -EINVAL; + + if (!(arg & PR_TAGGED_ADDR_ENABLE)) + pmlen = PMLEN_0; + + if (mmap_write_lock_killable(mm)) + return -EINTR; + + if (test_bit(MM_CONTEXT_LOCK_PMLEN, &mm->context.flags) && mm->context.pmlen != pmlen) { + mmap_write_unlock(mm); + return -EBUSY; + } envcfg_update_bits(task, ENVCFG_PMM, pmm); + mm->context.pmlen = pmlen; + + mmap_write_unlock(mm); return 0; } @@ -298,6 +333,10 @@ long get_tagged_addr_ctrl(struct task_struct *task) if (is_compat_thread(ti)) return -EINVAL; + /* + * The mm context's pmlen is set only when the tagged address ABI is + * enabled, so the effective PMLEN must be extracted from envcfg.PMM. + */ switch (task->thread.envcfg & ENVCFG_PMM) { case ENVCFG_PMM_PMLEN_7: ret = FIELD_PREP(PR_PMLEN_MASK, PMLEN_7); @@ -307,6 +346,9 @@ long get_tagged_addr_ctrl(struct task_struct *task) break; } + if (task->mm->context.pmlen) + ret |= PR_TAGGED_ADDR_ENABLE; + return ret; } @@ -316,6 +358,24 @@ static bool try_to_set_pmm(unsigned long value) return (csr_read_clear(CSR_ENVCFG, ENVCFG_PMM) & ENVCFG_PMM) == value; } +/* + * Global sysctl to disable the tagged user addresses support. 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Wed, 16 Oct 2024 13:28:29 -0700 (PDT) Received: from sw06.internal.sifive.com ([4.53.31.132]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2e3e08f8f89sm228613a91.38.2024.10.16.13.28.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Oct 2024 13:28:29 -0700 (PDT) From: Samuel Holland To: Palmer Dabbelt , linux-riscv@lists.infradead.org Cc: Catalin Marinas , Atish Patra , linux-kselftest@vger.kernel.org, Rob Herring , "Kirill A . Shutemov" , Shuah Khan , devicetree@vger.kernel.org, Anup Patel , linux-kernel@vger.kernel.org, Jonathan Corbet , kvm-riscv@lists.infradead.org, Conor Dooley , kasan-dev@googlegroups.com, linux-doc@vger.kernel.org, Evgenii Stepanov , Charlie Jenkins , Krzysztof Kozlowski , Samuel Holland Subject: [PATCH v5 07/10] riscv: selftests: Add a pointer masking test Date: Wed, 16 Oct 2024 13:27:48 -0700 Message-ID: <20241016202814.4061541-8-samuel.holland@sifive.com> X-Mailer: git-send-email 2.45.1 In-Reply-To: <20241016202814.4061541-1-samuel.holland@sifive.com> References: <20241016202814.4061541-1-samuel.holland@sifive.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 This test covers the behavior of the PR_SET_TAGGED_ADDR_CTRL and PR_GET_TAGGED_ADDR_CTRL prctl() operations, their effects on the userspace ABI, and their effects on the system call ABI. Reviewed-by: Charlie Jenkins Tested-by: Charlie Jenkins Signed-off-by: Samuel Holland --- Changes in v5: - Rename "pm" selftests directory to "abi" to be more generic - Fix -Wparentheses warnings - Fix order of operations when writing via the tagged pointer Changes in v2: - Rename "tags" directory to "pm" to avoid .gitignore rules - Add .gitignore file to ignore the compiled selftest binary - Write to a pipe to force dereferencing the user pointer - Handle SIGSEGV in the child process to reduce dmesg noise tools/testing/selftests/riscv/Makefile | 2 +- tools/testing/selftests/riscv/abi/.gitignore | 1 + tools/testing/selftests/riscv/abi/Makefile | 10 + .../selftests/riscv/abi/pointer_masking.c | 332 ++++++++++++++++++ 4 files changed, 344 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/riscv/abi/.gitignore create mode 100644 tools/testing/selftests/riscv/abi/Makefile create mode 100644 tools/testing/selftests/riscv/abi/pointer_masking.c diff --git a/tools/testing/selftests/riscv/Makefile b/tools/testing/selftests/riscv/Makefile index 7ce03d832b64..099b8c1f46f8 100644 --- a/tools/testing/selftests/riscv/Makefile +++ b/tools/testing/selftests/riscv/Makefile @@ -5,7 +5,7 @@ ARCH ?= $(shell uname -m 2>/dev/null || echo not) ifneq (,$(filter $(ARCH),riscv)) -RISCV_SUBTARGETS ?= hwprobe vector mm sigreturn +RISCV_SUBTARGETS ?= abi hwprobe mm sigreturn vector else RISCV_SUBTARGETS := endif diff --git a/tools/testing/selftests/riscv/abi/.gitignore b/tools/testing/selftests/riscv/abi/.gitignore new file mode 100644 index 000000000000..b38358f91c4d --- /dev/null +++ b/tools/testing/selftests/riscv/abi/.gitignore @@ -0,0 +1 @@ +pointer_masking diff --git a/tools/testing/selftests/riscv/abi/Makefile b/tools/testing/selftests/riscv/abi/Makefile new file mode 100644 index 000000000000..ed82ff9c664e --- /dev/null +++ b/tools/testing/selftests/riscv/abi/Makefile @@ -0,0 +1,10 @@ +# SPDX-License-Identifier: GPL-2.0 + +CFLAGS += -I$(top_srcdir)/tools/include + +TEST_GEN_PROGS := pointer_masking + +include ../../lib.mk + +$(OUTPUT)/pointer_masking: pointer_masking.c + $(CC) -static -o$@ $(CFLAGS) $(LDFLAGS) $^ diff --git a/tools/testing/selftests/riscv/abi/pointer_masking.c b/tools/testing/selftests/riscv/abi/pointer_masking.c new file mode 100644 index 000000000000..dee41b7ee3e3 --- /dev/null +++ b/tools/testing/selftests/riscv/abi/pointer_masking.c @@ -0,0 +1,332 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#include +#include +#include +#include +#include +#include +#include +#include + +#include "../../kselftest.h" + +#ifndef PR_PMLEN_SHIFT +#define PR_PMLEN_SHIFT 24 +#endif +#ifndef PR_PMLEN_MASK +#define PR_PMLEN_MASK (0x7fUL << PR_PMLEN_SHIFT) +#endif + +static int dev_zero; + +static int pipefd[2]; + +static sigjmp_buf jmpbuf; + +static void sigsegv_handler(int sig) +{ + siglongjmp(jmpbuf, 1); +} + +static int min_pmlen; +static int max_pmlen; + +static inline bool valid_pmlen(int pmlen) +{ + return pmlen == 0 || pmlen == 7 || pmlen == 16; +} + +static void test_pmlen(void) +{ + ksft_print_msg("Testing available PMLEN values\n"); + + for (int request = 0; request <= 16; request++) { + int pmlen, ret; + + ret = prctl(PR_SET_TAGGED_ADDR_CTRL, request << PR_PMLEN_SHIFT, 0, 0, 0); + if (ret) + goto pr_set_error; + + ret = prctl(PR_GET_TAGGED_ADDR_CTRL, 0, 0, 0, 0); + ksft_test_result(ret >= 0, "PMLEN=%d PR_GET_TAGGED_ADDR_CTRL\n", request); + if (ret < 0) + goto pr_get_error; + + pmlen = (ret & PR_PMLEN_MASK) >> PR_PMLEN_SHIFT; + ksft_test_result(pmlen >= request, "PMLEN=%d constraint\n", request); + ksft_test_result(valid_pmlen(pmlen), "PMLEN=%d validity\n", request); + + if (min_pmlen == 0) + min_pmlen = pmlen; + if (max_pmlen < pmlen) + max_pmlen = pmlen; + + continue; + +pr_set_error: + ksft_test_result_skip("PMLEN=%d PR_GET_TAGGED_ADDR_CTRL\n", request); +pr_get_error: + ksft_test_result_skip("PMLEN=%d constraint\n", request); + ksft_test_result_skip("PMLEN=%d validity\n", request); + } + + if (max_pmlen == 0) + ksft_exit_fail_msg("Failed to enable pointer masking\n"); +} + +static int set_tagged_addr_ctrl(int pmlen, bool tagged_addr_abi) +{ + int arg, ret; + + arg = pmlen << PR_PMLEN_SHIFT | tagged_addr_abi; + ret = prctl(PR_SET_TAGGED_ADDR_CTRL, arg, 0, 0, 0); + if (!ret) { + ret = prctl(PR_GET_TAGGED_ADDR_CTRL, 0, 0, 0, 0); + if (ret == arg) + return 0; + } + + return ret < 0 ? -errno : -ENODATA; +} + +static void test_dereference_pmlen(int pmlen) +{ + static volatile int i; + volatile int *p; + int ret; + + ret = set_tagged_addr_ctrl(pmlen, false); + if (ret) + return ksft_test_result_error("PMLEN=%d setup (%d)\n", pmlen, ret); + + i = pmlen; + + if (pmlen) { + p = (volatile int *)((uintptr_t)&i | 1UL << (__riscv_xlen - pmlen)); + + /* These dereferences should succeed. */ + if (sigsetjmp(jmpbuf, 1)) + return ksft_test_result_fail("PMLEN=%d valid tag\n", pmlen); + if (*p != pmlen) + return ksft_test_result_fail("PMLEN=%d bad value\n", pmlen); + ++*p; + } + + p = (volatile int *)((uintptr_t)&i | 1UL << (__riscv_xlen - pmlen - 1)); + + /* These dereferences should raise SIGSEGV. */ + if (sigsetjmp(jmpbuf, 1)) + return ksft_test_result_pass("PMLEN=%d dereference\n", pmlen); + ++*p; + ksft_test_result_fail("PMLEN=%d invalid tag\n", pmlen); +} + +static void test_dereference(void) +{ + ksft_print_msg("Testing userspace pointer dereference\n"); + + signal(SIGSEGV, sigsegv_handler); + + test_dereference_pmlen(0); + test_dereference_pmlen(min_pmlen); + test_dereference_pmlen(max_pmlen); + + signal(SIGSEGV, SIG_DFL); +} + +static void execve_child_sigsegv_handler(int sig) +{ + exit(42); +} + +static int execve_child(void) +{ + static volatile int i; + volatile int *p = (volatile int *)((uintptr_t)&i | 1UL << (__riscv_xlen - 7)); + + signal(SIGSEGV, execve_child_sigsegv_handler); + + /* This dereference should raise SIGSEGV. */ + return *p; +} + +static void test_fork_exec(void) +{ + int ret, status; + + ksft_print_msg("Testing fork/exec behavior\n"); + + ret = set_tagged_addr_ctrl(min_pmlen, false); + if (ret) + return ksft_test_result_error("setup (%d)\n", ret); + + if (fork()) { + wait(&status); + ksft_test_result(WIFEXITED(status) && WEXITSTATUS(status) == 42, + "dereference after fork\n"); + } else { + static volatile int i = 42; + volatile int *p; + + p = (volatile int *)((uintptr_t)&i | 1UL << (__riscv_xlen - min_pmlen)); + + /* This dereference should succeed. */ + exit(*p); + } + + if (fork()) { + wait(&status); + ksft_test_result(WIFEXITED(status) && WEXITSTATUS(status) == 42, + "dereference after fork+exec\n"); + } else { + /* Will call execve_child(). */ + execve("/proc/self/exe", (char *const []) { "", NULL }, NULL); + } +} + +static void test_tagged_addr_abi_sysctl(void) +{ + char value; + int fd; + + ksft_print_msg("Testing tagged address ABI sysctl\n"); + + fd = open("/proc/sys/abi/tagged_addr_disabled", O_WRONLY); + if (fd < 0) { + ksft_test_result_skip("failed to open sysctl file\n"); + ksft_test_result_skip("failed to open sysctl file\n"); + return; + } + + value = '1'; + pwrite(fd, &value, 1, 0); + ksft_test_result(set_tagged_addr_ctrl(min_pmlen, true) == -EINVAL, + "sysctl disabled\n"); + + value = '0'; + pwrite(fd, &value, 1, 0); + ksft_test_result(set_tagged_addr_ctrl(min_pmlen, true) == 0, + "sysctl enabled\n"); + + set_tagged_addr_ctrl(0, false); + + close(fd); +} + +static void test_tagged_addr_abi_pmlen(int pmlen) +{ + int i, *p, ret; + + i = ~pmlen; + + if (pmlen) { + p = (int *)((uintptr_t)&i | 1UL << (__riscv_xlen - pmlen)); + + ret = set_tagged_addr_ctrl(pmlen, false); + if (ret) + return ksft_test_result_error("PMLEN=%d ABI disabled setup (%d)\n", + pmlen, ret); + + ret = write(pipefd[1], p, sizeof(*p)); + if (ret >= 0 || errno != EFAULT) + return ksft_test_result_fail("PMLEN=%d ABI disabled write\n", pmlen); + + ret = read(dev_zero, p, sizeof(*p)); + if (ret >= 0 || errno != EFAULT) + return ksft_test_result_fail("PMLEN=%d ABI disabled read\n", pmlen); + + if (i != ~pmlen) + return ksft_test_result_fail("PMLEN=%d ABI disabled value\n", pmlen); + + ret = set_tagged_addr_ctrl(pmlen, true); + if (ret) + return ksft_test_result_error("PMLEN=%d ABI enabled setup (%d)\n", + pmlen, ret); + + ret = write(pipefd[1], p, sizeof(*p)); + if (ret != sizeof(*p)) + return ksft_test_result_fail("PMLEN=%d ABI enabled write\n", pmlen); + + ret = read(dev_zero, p, sizeof(*p)); + if (ret != sizeof(*p)) + return ksft_test_result_fail("PMLEN=%d ABI enabled read\n", pmlen); + + if (i) + return ksft_test_result_fail("PMLEN=%d ABI enabled value\n", pmlen); + + i = ~pmlen; + } else { + /* The tagged address ABI cannot be enabled when PMLEN == 0. */ + ret = set_tagged_addr_ctrl(pmlen, true); + if (ret != -EINVAL) + return ksft_test_result_error("PMLEN=%d ABI setup (%d)\n", + pmlen, ret); + } + + p = (int *)((uintptr_t)&i | 1UL << (__riscv_xlen - pmlen - 1)); + + ret = write(pipefd[1], p, sizeof(*p)); + if (ret >= 0 || errno != EFAULT) + return ksft_test_result_fail("PMLEN=%d invalid tag write (%d)\n", pmlen, errno); + + ret = read(dev_zero, p, sizeof(*p)); + if (ret >= 0 || errno != EFAULT) + return ksft_test_result_fail("PMLEN=%d invalid tag read\n", pmlen); + + if (i != ~pmlen) + return ksft_test_result_fail("PMLEN=%d invalid tag value\n", pmlen); + + ksft_test_result_pass("PMLEN=%d tagged address ABI\n", pmlen); +} + +static void test_tagged_addr_abi(void) +{ + ksft_print_msg("Testing tagged address ABI\n"); + + test_tagged_addr_abi_pmlen(0); + test_tagged_addr_abi_pmlen(min_pmlen); + test_tagged_addr_abi_pmlen(max_pmlen); +} + +static struct test_info { + unsigned int nr_tests; + void (*test_fn)(void); +} tests[] = { + { .nr_tests = 17 * 3, test_pmlen }, + { .nr_tests = 3, test_dereference }, + { .nr_tests = 2, test_fork_exec }, + { .nr_tests = 2, test_tagged_addr_abi_sysctl }, + { .nr_tests = 3, test_tagged_addr_abi }, +}; + +int main(int argc, char **argv) +{ + unsigned int plan = 0; + int ret; + + /* Check if this is the child process after execve(). */ + if (!argv[0][0]) + return execve_child(); 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Wed, 16 Oct 2024 13:28:33 -0700 (PDT) Received: from sw06.internal.sifive.com ([4.53.31.132]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2e3e08f8f89sm228613a91.38.2024.10.16.13.28.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Oct 2024 13:28:32 -0700 (PDT) From: Samuel Holland To: Palmer Dabbelt , linux-riscv@lists.infradead.org Cc: Catalin Marinas , Atish Patra , linux-kselftest@vger.kernel.org, Rob Herring , "Kirill A . Shutemov" , Shuah Khan , devicetree@vger.kernel.org, Anup Patel , linux-kernel@vger.kernel.org, Jonathan Corbet , kvm-riscv@lists.infradead.org, Conor Dooley , kasan-dev@googlegroups.com, linux-doc@vger.kernel.org, Evgenii Stepanov , Charlie Jenkins , Krzysztof Kozlowski , Samuel Holland Subject: [PATCH v5 09/10] RISC-V: KVM: Allow Smnpm and Ssnpm extensions for guests Date: Wed, 16 Oct 2024 13:27:50 -0700 Message-ID: <20241016202814.4061541-10-samuel.holland@sifive.com> X-Mailer: git-send-email 2.45.1 In-Reply-To: <20241016202814.4061541-1-samuel.holland@sifive.com> References: <20241016202814.4061541-1-samuel.holland@sifive.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The interface for controlling pointer masking in VS-mode is henvcfg.PMM, which is part of the Ssnpm extension, even though pointer masking in HS-mode is provided by the Smnpm extension. As a result, emulating Smnpm in the guest requires (only) Ssnpm on the host. The guest configures Smnpm through the SBI Firmware Features extension, which KVM does not yet implement, so currently the ISA extension has no visible effect on the guest, and thus it cannot be disabled. Ssnpm is configured using the senvcfg CSR within the guest, so that extension cannot be hidden from the guest without intercepting writes to the CSR. Signed-off-by: Samuel Holland --- Changes in v5: - Do not allow Smnpm to be disabled, as suggested by Anup Changes in v2: - New patch for v2 arch/riscv/include/uapi/asm/kvm.h | 2 ++ arch/riscv/kvm/vcpu_onereg.c | 4 ++++ 2 files changed, 6 insertions(+) diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h index e97db3296456..4f24201376b1 100644 --- a/arch/riscv/include/uapi/asm/kvm.h +++ b/arch/riscv/include/uapi/asm/kvm.h @@ -175,6 +175,8 @@ enum KVM_RISCV_ISA_EXT_ID { KVM_RISCV_ISA_EXT_ZCF, KVM_RISCV_ISA_EXT_ZCMOP, KVM_RISCV_ISA_EXT_ZAWRS, + KVM_RISCV_ISA_EXT_SMNPM, + KVM_RISCV_ISA_EXT_SSNPM, KVM_RISCV_ISA_EXT_MAX, }; diff --git a/arch/riscv/kvm/vcpu_onereg.c b/arch/riscv/kvm/vcpu_onereg.c index b319c4c13c54..5b68490ad9b7 100644 --- a/arch/riscv/kvm/vcpu_onereg.c +++ b/arch/riscv/kvm/vcpu_onereg.c @@ -34,9 +34,11 @@ static const unsigned long kvm_isa_ext_arr[] = { [KVM_RISCV_ISA_EXT_M] = RISCV_ISA_EXT_m, [KVM_RISCV_ISA_EXT_V] = RISCV_ISA_EXT_v, /* Multi letter extensions (alphabetically sorted) */ + [KVM_RISCV_ISA_EXT_SMNPM] = RISCV_ISA_EXT_SSNPM, KVM_ISA_EXT_ARR(SMSTATEEN), KVM_ISA_EXT_ARR(SSAIA), KVM_ISA_EXT_ARR(SSCOFPMF), + KVM_ISA_EXT_ARR(SSNPM), KVM_ISA_EXT_ARR(SSTC), KVM_ISA_EXT_ARR(SVINVAL), KVM_ISA_EXT_ARR(SVNAPOT), @@ -127,8 +129,10 @@ static bool kvm_riscv_vcpu_isa_disable_allowed(unsigned long ext) case KVM_RISCV_ISA_EXT_C: case KVM_RISCV_ISA_EXT_I: case KVM_RISCV_ISA_EXT_M: + case KVM_RISCV_ISA_EXT_SMNPM: /* There is not architectural config bit to disable sscofpmf completely */ case KVM_RISCV_ISA_EXT_SSCOFPMF: + case KVM_RISCV_ISA_EXT_SSNPM: case KVM_RISCV_ISA_EXT_SSTC: case KVM_RISCV_ISA_EXT_SVINVAL: case KVM_RISCV_ISA_EXT_SVNAPOT: