| Message ID | 20200520172800.8499-3-richard.henderson@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | linux-user: User support for AArch64 BTI | expand |
On Wed, 20 May 2020 at 18:28, Richard Henderson <richard.henderson@linaro.org> wrote: > > Transform the prot bit to a qemu internal page bit, and save > it in the page tables. > > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> > --- > include/exec/cpu-all.h | 2 ++ > linux-user/syscall_defs.h | 4 ++++ > linux-user/mmap.c | 16 ++++++++++++++++ > target/arm/translate-a64.c | 6 +++--- > 4 files changed, 25 insertions(+), 3 deletions(-) > > diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h > index d14374bdd4..2bd023d692 100644 > --- a/include/exec/cpu-all.h > +++ b/include/exec/cpu-all.h > @@ -276,6 +276,8 @@ extern intptr_t qemu_host_page_mask; > /* FIXME: Code that sets/uses this is broken and needs to go away. */ > #define PAGE_RESERVED 0x0020 > #endif > +/* Target-specific bits that will be used via page_get_flags(). */ > +#define PAGE_TARGET_1 0x0080 I think it would also be nice to have /* Target-specific names for the target-specific bits */ #ifdef TARGET_AARCH64 #define PAGE_BTI PAGE_TARGET_1 #endif which can then (a) act as documentation of which PAGE_TARGET_n each target is actually using and (b) mean that code that's using the target-specific bits can use more friendly names. Otherwise Reviewed-by: Peter Maydell <peter.maydell@linaro.org> thanks -- PMM
diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h index d14374bdd4..2bd023d692 100644 --- a/include/exec/cpu-all.h +++ b/include/exec/cpu-all.h @@ -276,6 +276,8 @@ extern intptr_t qemu_host_page_mask; /* FIXME: Code that sets/uses this is broken and needs to go away. */ #define PAGE_RESERVED 0x0020 #endif +/* Target-specific bits that will be used via page_get_flags(). */ +#define PAGE_TARGET_1 0x0080 #if defined(CONFIG_USER_ONLY) void page_dump(FILE *f); diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h index 152ec637cb..36bdafb3f1 100644 --- a/linux-user/syscall_defs.h +++ b/linux-user/syscall_defs.h @@ -1194,6 +1194,10 @@ struct target_winsize { #define TARGET_PROT_SEM 0x08 #endif +#ifdef TARGET_AARCH64 +#define TARGET_PROT_BTI 0x10 +#endif + /* Common */ #define TARGET_MAP_SHARED 0x01 /* Share changes */ #define TARGET_MAP_PRIVATE 0x02 /* Changes are private */ diff --git a/linux-user/mmap.c b/linux-user/mmap.c index 84662c3311..40f03e3174 100644 --- a/linux-user/mmap.c +++ b/linux-user/mmap.c @@ -83,6 +83,22 @@ static int validate_prot_to_pageflags(int *host_prot, int prot) *host_prot = (prot & (PROT_READ | PROT_WRITE)) | (prot & PROT_EXEC ? PROT_READ : 0); +#ifdef TARGET_AARCH64 + /* + * The PROT_BTI bit is only accepted if the cpu supports the feature. + * Since this is the unusual case, don't bother checking unless + * the bit has been requested. If set and valid, record the bit + * within QEMU's page_flags as PAGE_TARGET_1. + */ + if (prot & TARGET_PROT_BTI) { + ARMCPU *cpu = ARM_CPU(thread_cpu); + if (cpu_isar_feature(aa64_bti, cpu)) { + valid |= TARGET_PROT_BTI; + page_flags |= PAGE_TARGET_1; + } + } +#endif + return prot & ~valid ? 0 : page_flags; } diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c index 991e451644..59ae236c84 100644 --- a/target/arm/translate-a64.c +++ b/target/arm/translate-a64.c @@ -13989,10 +13989,10 @@ static void disas_data_proc_simd_fp(DisasContext *s, uint32_t insn) */ static bool is_guarded_page(CPUARMState *env, DisasContext *s) { -#ifdef CONFIG_USER_ONLY - return false; /* FIXME */ -#else uint64_t addr = s->base.pc_first; +#ifdef CONFIG_USER_ONLY + return page_get_flags(addr) & PAGE_TARGET_1; +#else int mmu_idx = arm_to_core_mmu_idx(s->mmu_idx); unsigned int index = tlb_index(env, mmu_idx, addr); CPUTLBEntry *entry = tlb_entry(env, mmu_idx, addr);
Transform the prot bit to a qemu internal page bit, and save it in the page tables. Signed-off-by: Richard Henderson <richard.henderson@linaro.org> --- include/exec/cpu-all.h | 2 ++ linux-user/syscall_defs.h | 4 ++++ linux-user/mmap.c | 16 ++++++++++++++++ target/arm/translate-a64.c | 6 +++--- 4 files changed, 25 insertions(+), 3 deletions(-) -- 2.20.1