Re: [Crash-utility] [PATCH] arm64: Use VA_BITS for page_offset calculation

Hi, Here is a patch for the issue reported by Ankur. Could you help test this with your ramdumps and arm64 machines?

-- From 028ddf655c847c16cce23198017d2ff0169bb4de Mon Sep 17 00:00:00 2001 From: Kazuhito Hagio <k-hagio-ab(a)nec.com&gt; Date: Mon, 25 Oct 2021 16:53:26 +0900 Subject: [PATCH] arm64: Use VA_BITS for page_offset calculation Commit 167d37e347fe ("arm64: assign page_offset with VA_BITS kernel configuration value") changed the page_offset calculation from using VA_BITS_ACTUAL to CONFIG_ARM64_VA_BITS. This caused an error for ramdumps without vmcoreinfo like this: crash: vmlinux and /var/tmp/ramdump_elf_XUtCMT do not match! Set the vmcoreinfo value to VA_BITS if available, and use VA_BITS for page_offset calculation instead. Also remove ARM64_FLIP_PAGE_OFFSET_ACTUAL because it's not used actually. Reported-by: Ankur Bansal <er.ankurbansal(a)gmail.com&gt; Signed-off-by: Kazuhito Hagio <k-hagio-ab(a)nec.com&gt; --- arm64.c | 5 ++++- defs.h | 4 +--- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/arm64.c b/arm64.c index 7069312671cf..3dcbcc642fda 100644 --- a/arm64.c +++ b/arm64.c @@ -404,7 +404,7 @@ arm64_init(int when) fprintf(fp, "CONFIG_ARM64_VA_BITS: %ld\n", ms->CONFIG_ARM64_VA_BITS); fprintf(fp, " VA_BITS_ACTUAL: %ld\n", ms->VA_BITS_ACTUAL); fprintf(fp, "(calculated) VA_BITS: %ld\n", ms->VA_BITS); - fprintf(fp, " PAGE_OFFSET: %lx\n", ARM64_FLIP_PAGE_OFFSET_ACTUAL); + fprintf(fp, " PAGE_OFFSET: %lx\n", ARM64_FLIP_PAGE_OFFSET); fprintf(fp, " VA_START: %lx\n", ms->VA_START); fprintf(fp, " modules: %lx - %lx\n", ms->modules_vaddr, ms->modules_end); fprintf(fp, " vmalloc: %lx - %lx\n", ms->vmalloc_start_addr, ms->vmalloc_end); @@ -4031,6 +4031,9 @@ arm64_calc_VA_BITS(void) error(FATAL, "cannot determine VA_BITS_ACTUAL\n"); } + if (machdep->machspec->CONFIG_ARM64_VA_BITS) + machdep->machspec->VA_BITS = machdep->machspec->CONFIG_ARM64_VA_BITS; + /* * The mm flip commit is introduced before 52-bits VA, which is before the * commit to export NUMBER(TCR_EL1_T1SZ) diff --git a/defs.h b/defs.h index 8b356d5e8959..971005596506 100644 --- a/defs.h +++ b/defs.h @@ -3238,9 +3238,7 @@ typedef signed int s32; #define ARM64_PAGE_OFFSET ((0xffffffffffffffffUL) \ << (machdep->machspec->VA_BITS - 1)) /* kernels >= v5.4 the kernel VA space is flipped */ -#define ARM64_FLIP_PAGE_OFFSET (-(1UL) << machdep->machspec->CONFIG_ARM64_VA_BITS) -#define ARM64_FLIP_PAGE_OFFSET_ACTUAL ((0xffffffffffffffffUL) \ - - ((1UL) << machdep->machspec->VA_BITS_ACTUAL) + 1) +#define ARM64_FLIP_PAGE_OFFSET (-(1UL) << machdep->machspec->VA_BITS) #define ARM64_USERSPACE_TOP ((1UL) << machdep->machspec->VA_BITS) #define ARM64_USERSPACE_TOP_ACTUAL ((1UL) << machdep->machspec->VA_BITS_ACTUAL) -- 2.27.0