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[66.187.233.206]) by smtp.gmail.com with ESMTPSA id e3sm2260682qts.34.2021.06.08.03.34.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 08 Jun 2021 03:34:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=J48k4WcLJ93C6a4z5qvH4NdBXcXofCtpkZgQyGSY/Bw=; b=f9s3tlGdv+Y1LSpT+BfcUXtXM2IKhT7mXXeAXGNZVv9grY44lipLCrOVlyDsoNqFHY bgRAtbzCs0cwsYch3IqjUkRg21qKS89A0AvC/4hjJpGDX8cSkRKtUGIzPDwgYi9y+T31 8TAJrWW5ruMltyaKoq0xV+xGYunqeX5PTvyvcT1gXDjiJ+SWx42GiARauzNeLu799E7w lDoMh2hpfafy5xC8CoMGZ4dlEujFKrS0wSuarkwsCOAPKTSiLxeRJBlLEVts/CKlGdvE mMCenIyU7M1vbyvJ3RVCjBI/ZXYJixFMzu/bSlpoKLuIDf0YZxDH93cd2ya4ma5A6ezs dAuw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=J48k4WcLJ93C6a4z5qvH4NdBXcXofCtpkZgQyGSY/Bw=; b=mSniKYzeQUk7xLQAsLB9wcJpT7j+dzusH9gjdQ0JN+177BSIYuojf5p1k3JgiOIJVX Wm+oZRVWLrpdR/uLyFgVgdCkvQTJOlc1AKPYCfr4auAz5+5lRvTMkLEAqDKo+5AE5++e 4V0NRdEiLk+Q1t/9Si60Zu4pK2fgymD13aLqB89ZRntqbhxLYTZy6MEDx8WlkVgo+hPg 3Ks8jSQ9nDaDSiF7ezcLySeSUmQpXgfzhieJqB3wS6SJ+pB0tteJMpUcNJ9+Cy7fKHN5 A4SiEd3w11WUKYHkYr4VFfPxoJ8GcoIWsutB7egSdTkRAsZofML+UhkVeYXBJ5aF3V6W Un7w== X-Gm-Message-State: AOAM531KGJZINcI63Akv+nxUB0+wwSNo8IFOZBbx/4lxAOPcHM2E06j1 HtO10QxYS6ttZs/qfghKoA== X-Google-Smtp-Source: ABdhPJzwosaCGBBwjiwr3ftTAMod+g7XPn30t+/0BRzJxX9QrrUMaPQenkgIE6i5E4uZVVsWsh1sig== X-Received: by 2002:a0c:ed46:: with SMTP id v6mr22752280qvq.46.1623148451751; Tue, 08 Jun 2021 03:34:11 -0700 (PDT) From: Pingfan Liu Cc: Pingfan Liu , Bhupesh Sharma , Kazuhito Hagio , Dave Young , Baoquan He , Boris Petkov , Ingo Molnar , Thomas Gleixner , James Morse , Mark Rutland , Will Deacon , Catalin Marinas , Michael Ellerman , Paul Mackerras , Benjamin Herrenschmidt , Dave Anderson , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, x86@kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH] crash_core, vmcoreinfo: Append 'SECTION_SIZE_BITS' to vmcoreinfo Date: Tue, 8 Jun 2021 06:33:59 -0400 Message-Id: <20210608103359.84907-1-kernelfans@gmail.com> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" As mentioned in kernel commit 1d50e5d0c505 ("crash_core, vmcoreinfo: Append 'MAX_PHYSMEM_BITS' to vmcoreinfo"), SECTION_SIZE_BITS in the formula: #define SECTIONS_SHIFT (MAX_PHYSMEM_BITS - SECTION_SIZE_BITS) Besides SECTIONS_SHIFT, SECTION_SIZE_BITS is also used to calculate PAGES_PER_SECTION in makedumpfile just like kernel. Unfortunately, this arch-dependent macro SECTION_SIZE_BITS changes, e.g. recently in kernel commit f0b13ee23241 ("arm64/sparsemem: reduce SECTION_SIZE_BITS"). But user space wants a stable interface to get this info. Such info is impossible to be deduced from a crashdump vmcore. Hence append SECTION_SIZE_BITS to vmcoreinfo. Signed-off-by: Pingfan Liu Cc: Bhupesh Sharma Cc: Kazuhito Hagio Cc: Dave Young Cc: Baoquan He Cc: Boris Petkov Cc: Ingo Molnar Cc: Thomas Gleixner Cc: James Morse Cc: Mark Rutland Cc: Will Deacon Cc: Catalin Marinas Cc: Michael Ellerman Cc: Paul Mackerras Cc: Benjamin Herrenschmidt Cc: Dave Anderson Cc: linuxppc-dev@lists.ozlabs.org Cc: linux-kernel@vger.kernel.org Cc: kexec@lists.infradead.org Cc: x86@kernel.org Cc: linux-arm-kernel@lists.infradead.org --- kernel/crash_core.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/crash_core.c b/kernel/crash_core.c index 825284baaf46..684a6061a13a 100644 --- a/kernel/crash_core.c +++ b/kernel/crash_core.c @@ -464,6 +464,7 @@ static int __init crash_save_vmcoreinfo_init(void) VMCOREINFO_LENGTH(mem_section, NR_SECTION_ROOTS); VMCOREINFO_STRUCT_SIZE(mem_section); VMCOREINFO_OFFSET(mem_section, section_mem_map); + VMCOREINFO_NUMBER(SECTION_SIZE_BITS); VMCOREINFO_NUMBER(MAX_PHYSMEM_BITS); #endif VMCOREINFO_STRUCT_SIZE(page); --=20 2.29.2