On Wed, Sep 18, 2024 at 3:37 PM <devel-requ...@lists.crash-utility.osci.io>
wrote:
> Date: Wed, 18 Sep 2024 11:42:05 +1200
> From: Tao Liu <l...@redhat.com>
> Subject: [Crash-utility] [PATCH v1 3/3] ppc64: fix the bug eframe
> won't print for newer kernel
> To: devel@lists.crash-utility.osci.io
> Cc: adit...@linux.ibm.com, Tao Liu <l...@redhat.com>
> Message-ID: <20240917234205.7783-4-l...@redhat.com>
> Content-Type: text/plain; charset="US-ASCII"; x-default=true
>
> The value of EXCP_FRAME_MARKER is outdated for kernel>=6.1.0, and also
> its offset is changed since kernel>=6.2.0. This patch will fix the issue
>
Can you help to add the related kernel commits to the patch log?
Otherwise I have to find it and check why the crash tool needs to be
changed.
by updating its values.
>
> Before:
> crash> bt
> ...
> #8 [c00000000a327b80] system_call_exception at c000000000031a30
> #9 [c00000000a327e50] system_call_vectored_common at c00000000000d05c
>
> After:
> crash> bt
> ...
> #8 [c00000000a327b80] system_call_exception at c000000000031a30
> #9 [c00000000a327e50] system_call_vectored_common at c00000000000d05c
> System Call Vectored [3000] exception frame:
> R0: 0000000000000004 R1: 00007fffc3345f40 R2: 0000000000100000
> R3: 0000000000000001 R4: 000000012572c620 R5: 0000000000000002
> R6: 0000000000000001 R7: 0000000000000004 R8: 0000000000000001
> ...
>
> Signed-off-by: Tao Liu <l...@redhat.com>
> ---
> defs.h | 5 ++++-
> ppc64.c | 37 +++++++++++++++++++++++++++----------
> 2 files changed, 31 insertions(+), 11 deletions(-)
>
> diff --git a/defs.h b/defs.h
> index d5cb8cc..ceeb6cc 100644
> --- a/defs.h
> +++ b/defs.h
> @@ -4645,7 +4645,10 @@ struct efi_memory_desc_t {
>
> #define STACK_SWITCH_FRAME_REGS 48
> #define STACK_FRAME_OVERHEAD 112
> -#define EXCP_FRAME_MARKER 0x7265677368657265
> +#define EXCP_FRAME_MARKER \
> + (THIS_KERNEL_VERSION >= LINUX(6,1,0) ? \
> + (__BYTE_ORDER == __BIG_ENDIAN ? 0x52454753 : 0x53474552) : \
> + 0x7265677368657265)
>
>
Here, a code comment is needed, where does the magic number come from?
#define _SECTION_SIZE_BITS 24
> #define _MAX_PHYSMEM_BITS 44
> diff --git a/ppc64.c b/ppc64.c
> index 8af7b8a..5416281 100644
> --- a/ppc64.c
> +++ b/ppc64.c
> @@ -2217,19 +2217,34 @@ ppc64_back_trace(struct gnu_request *req, struct
> bt_info *bt)
> eframe_found = TRUE;
> else if (STREQ(req->name, ".ret_from_except"))
> eframe_found = TRUE;
> - } else if ((newsp - req->sp - STACK_FRAME_OVERHEAD) >=
> - sizeof(struct ppc64_pt_regs)) {
> - readmem(req->sp+0x60, KVADDR, &marker,
> - sizeof(ulong), "stack frame",
> FAULT_ON_ERROR);
> - if (marker == EXCP_FRAME_MARKER)
> - eframe_found = TRUE;
> + } else if (THIS_KERNEL_VERSION >= LINUX(6,2,0) &&
> is_ppc64_elf_abi_v2()) {
>
Looks like there is no better way? Can you help to describe the details?
Thanks
Lianbo
+ if ((newsp - req->sp - STACK_SWITCH_FRAME_REGS) >=
> + sizeof(struct ppc64_pt_regs)) {
> + readmem(req->sp+0x20, KVADDR, &marker,
> + sizeof(ulong), "stack frame",
> + FAULT_ON_ERROR);
> + }
> + } else {
> + if ((newsp - req->sp - STACK_FRAME_OVERHEAD) >=
> + sizeof(struct ppc64_pt_regs)) {
> + readmem(req->sp+0x60, KVADDR, &marker,
> + sizeof(ulong), "stack frame",
> + FAULT_ON_ERROR);
> + }
> }
> - if (eframe_found) {
> +
> + if (eframe_found || marker == EXCP_FRAME_MARKER) {
> char *efrm_str = NULL;
> struct ppc64_pt_regs regs;
> - readmem(req->sp+STACK_FRAME_OVERHEAD, KVADDR,
> ®s,
> - sizeof(struct ppc64_pt_regs),
> - "exception frame", FAULT_ON_ERROR);
> + if (THIS_KERNEL_VERSION >= LINUX(6,2,0) &&
> is_ppc64_elf_abi_v2()) {
> + readmem(req->sp+STACK_SWITCH_FRAME_REGS,
> KVADDR, ®s,
> + sizeof(struct ppc64_pt_regs),
> + "exception frame", FAULT_ON_ERROR);
> + } else {
> + readmem(req->sp+STACK_FRAME_OVERHEAD,
> KVADDR, ®s,
> + sizeof(struct ppc64_pt_regs),
> + "exception frame", FAULT_ON_ERROR);
> + }
>
> efrm_str = ppc64_check_eframe(®s);
> if (efrm_str) {
> @@ -2440,6 +2455,8 @@ ppc64_check_eframe(struct ppc64_pt_regs *regs)
> return("Denormalisation");
> case 0x1700:
> return("Altivec Assist");
> + case 0x3000:
> + return("System Call Vectored");
> }
>
> /* No exception frame exists */
> --
> 2.40.1
>
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