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[98.147.55.211]) by smtp.gmail.com with ESMTPSA id h26-20020aa786da000000b006e555d40951sm533465pfo.188.2024.02.27.10.48.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Feb 2024 10:48:52 -0800 (PST) From: Richard Henderson To: qemu-devel@nongnu.org Cc: alex.bennee@linaro.org Subject: [PATCH 12/14] linux-user/elfload: Simplify vma_dump_size Date: Tue, 27 Feb 2024 08:48:31 -1000 Message-Id: <20240227184833.193836-13-richard.henderson@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240227184833.193836-1-richard.henderson@linaro.org> References: <20240227184833.193836-1-richard.henderson@linaro.org> MIME-Version: 1.0 Received-SPF: pass client-ip=2607:f8b0:4864:20::334; envelope-from=richard.henderson@linaro.org; helo=mail-ot1-x334.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+patch=linaro.org@nongnu.org Sender: qemu-devel-bounces+patch=linaro.org@nongnu.org Use the flags that we've already saved in order to test accessibility. Use g2h_untagged and compare guest memory directly instead of copy_from_user. Signed-off-by: Richard Henderson --- linux-user/elfload.c | 34 ++++++++++------------------------ 1 file changed, 10 insertions(+), 24 deletions(-) diff --git a/linux-user/elfload.c b/linux-user/elfload.c index 491e754f72..47b5ce3005 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -4166,37 +4166,23 @@ static int vma_get_mapping_count(const struct mm_struct *mm) */ static abi_ulong vma_dump_size(const struct vm_area_struct *vma) { - /* if we cannot even read the first page, skip it */ - if (!access_ok_untagged(VERIFY_READ, vma->vma_start, TARGET_PAGE_SIZE)) - return (0); + /* The area must be readable. */ + if (!(vma->vma_flags & PROT_READ)) { + return 0; + } /* * Usually we don't dump executable pages as they contain * non-writable code that debugger can read directly from - * target library etc. However, thread stacks are marked - * also executable so we read in first page of given region - * and check whether it contains elf header. If there is - * no elf header, we dump it. + * target library etc. If there is no elf header, we dump it. */ - if (vma->vma_flags & PROT_EXEC) { - char page[TARGET_PAGE_SIZE]; - - if (copy_from_user(page, vma->vma_start, sizeof (page))) { - return 0; - } - if ((page[EI_MAG0] == ELFMAG0) && - (page[EI_MAG1] == ELFMAG1) && - (page[EI_MAG2] == ELFMAG2) && - (page[EI_MAG3] == ELFMAG3)) { - /* - * Mappings are possibly from ELF binary. Don't dump - * them. - */ - return (0); - } + if (!(vma->vma_flags & PROT_WRITE) && + (vma->vma_flags & PROT_EXEC) && + memcmp(g2h_untagged(vma->vma_start), ELFMAG, SELFMAG) == 0) { + return 0; } - return (vma->vma_end - vma->vma_start); + return vma->vma_end - vma->vma_start; } static int vma_walker(void *priv, target_ulong start, target_ulong end,