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([2602:47:d490:6901:9454:a46f:1c22:a7c6]) by smtp.gmail.com with ESMTPSA id a5-20020a17090a740500b00262e604724dsm6306451pjg.50.2023.08.05.20.37.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 05 Aug 2023 20:37:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1691293054; x=1691897854; 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=DQhgJn+xuWrfht0tZgQrit41wBeRtDQVHgOUdbJWgEM=; b=Hacv99WmJ9BnWfmFp/KhMmwj27f+9kUpj9WVeOdQwkjTRsabZU+Z8OKIraTjTaCJt4 oERBS4vAQxs/RzbtQiG5IsNLPvSEkWzdtDkX1sHwSTFAXRmtKRZNjVi6HZufhiva7OCq sfSd827Gt9D+lY5ZwCnDaIRJSMPbqLt5WCQGOlcr4v8hA1gZ16Z5k9iDbU0LDNDSiw29 EzZ/MuekqQr1Z/kJaMjeuzTSrKstVkuzSqRWG8qR+2Wq/fG6VJnIN/j8S5UpBawWje0m 9o7X/q1mmccpACQc4l/cf30RnxM6F3JFZnBhz9qwFhvbUXVuCVP9i/pbKUfwaycAdVv6 0JYw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1691293054; x=1691897854; 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=DQhgJn+xuWrfht0tZgQrit41wBeRtDQVHgOUdbJWgEM=; b=CL92eM0R6lmEE1m+Tt3OMRH0zviwnvB0LchPUODD/pd2uHWPWd4tN9PflIQfGb3vuy 7ey9NC5LIZimwukM7CG6UO8bh49NPtUy8HXVo6uUHLRLSxsU336SKN1xaE8kkxkjly7P HMtygs1PD5c097+/6ebyeog9jzLJT8q1BmE2csPJ5Je88OMl4DmvbDFzl7RIYAXc62as QvDfVgD5W6vtsnDZa3Qb9qQmBscBMDI1mDoxbJ1Jfu2zThhGGDgpuHgaKnLGtyQ5jOF4 TjtqtdRwUuSz2EVG1FJd62Q4MjO9DSlii9eGNsGAikrUIRWTNq9G1HGZEKrs7Rgzz/P6 tgIQ== X-Gm-Message-State: AOJu0YxUbP7QQ2kw/JfVrstC/i01vNaND/aYijzKeKXIff9WlG6Y4jDM Pwj8tsLi21gKAAwlVFm9rqfOasalUBXyXFnEoVk= X-Google-Smtp-Source: AGHT+IH/Pw3Iksvmc5NVxNyRQpyaOlLnBqEN/Bf2QuTCSjV4ldvWwhoPueZQLSp5DvfieiXVjsBXMA== X-Received: by 2002:a17:90b:ed4:b0:262:df91:cdce with SMTP id gz20-20020a17090b0ed400b00262df91cdcemr4447858pjb.23.1691293053748; Sat, 05 Aug 2023 20:37:33 -0700 (PDT) From: Richard Henderson To: qemu-devel@nongnu.org Cc: Helge Deller , Akihiko Odaki Subject: [PULL 21/24] linux-user: Do not adjust zero_bss for host page size Date: Sat, 5 Aug 2023 20:37:12 -0700 Message-Id: <20230806033715.244648-22-richard.henderson@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230806033715.244648-1-richard.henderson@linaro.org> References: <20230806033715.244648-1-richard.henderson@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2607:f8b0:4864:20::1032; envelope-from=richard.henderson@linaro.org; helo=mail-pj1-x1032.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 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+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @linaro.org) X-ZM-MESSAGEID: 1691293235098100003 Content-Type: text/plain; charset="utf-8" Rely on target_mmap to handle guest vs host page size mismatch. Tested-by: Helge Deller Reviewed-by: Helge Deller Reviewed-by: Akihiko Odaki Signed-off-by: Richard Henderson --- linux-user/elfload.c | 54 +++++++++++++++++++------------------------- 1 file changed, 23 insertions(+), 31 deletions(-) diff --git a/linux-user/elfload.c b/linux-user/elfload.c index e853a4ab33..66ab617bd1 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -2212,44 +2212,36 @@ static abi_ulong setup_arg_pages(struct linux_binpr= m *bprm, =20 /* Map and zero the bss. We need to explicitly zero any fractional pages after the data section (i.e. bss). */ -static void zero_bss(abi_ulong elf_bss, abi_ulong last_bss, int prot) +static void zero_bss(abi_ulong start_bss, abi_ulong end_bss, int prot) { - uintptr_t host_start, host_map_start, host_end; + abi_ulong align_bss; =20 - last_bss =3D TARGET_PAGE_ALIGN(last_bss); + align_bss =3D TARGET_PAGE_ALIGN(start_bss); + end_bss =3D TARGET_PAGE_ALIGN(end_bss); =20 - /* ??? There is confusion between qemu_real_host_page_size and - qemu_host_page_size here and elsewhere in target_mmap, which - may lead to the end of the data section mapping from the file - not being mapped. At least there was an explicit test and - comment for that here, suggesting that "the file size must - be known". The comment probably pre-dates the introduction - of the fstat system call in target_mmap which does in fact - find out the size. What isn't clear is if the workaround - here is still actually needed. For now, continue with it, - but merge it with the "normal" mmap that would allocate the bss. */ + if (start_bss < align_bss) { + int flags =3D page_get_flags(start_bss); =20 - host_start =3D (uintptr_t) g2h_untagged(elf_bss); - host_end =3D (uintptr_t) g2h_untagged(last_bss); - host_map_start =3D REAL_HOST_PAGE_ALIGN(host_start); - - if (host_map_start < host_end) { - void *p =3D mmap((void *)host_map_start, host_end - host_map_start, - prot, MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, -1, = 0); - if (p =3D=3D MAP_FAILED) { - perror("cannot mmap brk"); - exit(-1); + if (!(flags & PAGE_VALID)) { + /* Map the start of the bss. */ + align_bss -=3D TARGET_PAGE_SIZE; + } else if (flags & PAGE_WRITE) { + /* The page is already mapped writable. */ + memset(g2h_untagged(start_bss), 0, align_bss - start_bss); + } else { + /* Read-only zeros? */ + g_assert_not_reached(); } } =20 - /* Ensure that the bss page(s) are valid */ - if ((page_get_flags(last_bss-1) & prot) !=3D prot) { - page_set_flags(elf_bss & TARGET_PAGE_MASK, last_bss - 1, - prot | PAGE_VALID); - } - - if (host_start < host_map_start) { - memset((void *)host_start, 0, host_map_start - host_start); + if (align_bss < end_bss) { + abi_long err =3D target_mmap(align_bss, end_bss - align_bss, prot, + MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, + -1, 0); + if (err =3D=3D -1) { + perror("cannot mmap brk"); + exit(-1); + } } } =20 --=20 2.34.1