Re: [PATCH v3 5/6] s390/crash: Use note name macros
From: Dave Martin <Dave.Martin@arm.com>
Date: 2025-01-07 16:17:55
Also in:
kexec, linux-mm, linux-s390, lkml
Hi, On Tue, Jan 07, 2025 at 09:45:56PM +0900, Akihiko Odaki wrote:
quoted hunk ↗ jump to hunk
Use note name macros to match with the userspace's expectation. Signed-off-by: Akihiko Odaki <redacted> --- arch/s390/kernel/crash_dump.c | 62 ++++++++++++++++--------------------------- 1 file changed, 23 insertions(+), 39 deletions(-)diff --git a/arch/s390/kernel/crash_dump.c b/arch/s390/kernel/crash_dump.c
[...]
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@@ -281,10 +272,8 @@ static void *nt_init_name(void *buf, Elf64_Word type, void *desc, int d_len, return PTR_ADD(buf, len); } -static inline void *nt_init(void *buf, Elf64_Word type, void *desc, int d_len) -{ - return nt_init_name(buf, type, desc, d_len, nt_name(type)); -} +#define NT_INIT(buf, type, desc) \ + (nt_init_name((buf), NT_ ## type, &(desc), sizeof(desc), NN_ ## type))
Nit: this macro name clashes with the naming scheme in elf.h. I think that there is a (weak) convention that macros with upper-case names don't expand to a C function call; thus, a macro with an upper- case name can be invoked in places where a C function call would not be allowed. (This convention is not followed everywhere, though -- it's up to the maintainer what they prefer here.) (Note also, the outer parentheses and the parentheses around (buf) appear redundant -- although harmless?)
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/* * Calculate the size of ELF note@@ -300,10 +289,7 @@ static size_t nt_size_name(int d_len, const char *name) return size; } -static inline size_t nt_size(Elf64_Word type, int d_len) -{ - return nt_size_name(d_len, nt_name(type)); -} +#define NT_SIZE(type, desc) (nt_size_name(sizeof(desc), NN_ ## type))
Nit: name prefix clash (again); possibly redundant parentheses. [...]
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@@ -348,16 +332,16 @@ static size_t get_cpu_elf_notes_size(void) struct save_area *sa = NULL; size_t size; - size = nt_size(NT_PRSTATUS, sizeof(struct elf_prstatus)); - size += nt_size(NT_PRFPREG, sizeof(elf_fpregset_t)); - size += nt_size(NT_S390_TIMER, sizeof(sa->timer)); - size += nt_size(NT_S390_TODCMP, sizeof(sa->todcmp)); - size += nt_size(NT_S390_TODPREG, sizeof(sa->todpreg)); - size += nt_size(NT_S390_CTRS, sizeof(sa->ctrs)); - size += nt_size(NT_S390_PREFIX, sizeof(sa->prefix)); + size = NT_SIZE(PRSTATUS, struct elf_prstatus); + size += NT_SIZE(PRFPREG, elf_fpregset_t); + size += NT_SIZE(S390_TIMER, sa->timer); + size += NT_SIZE(S390_TODCMP, sa->todcmp); + size += NT_SIZE(S390_TODPREG, sa->todpreg); + size += NT_SIZE(S390_CTRS, sa->ctrs); + size += NT_SIZE(S390_PREFIX, sa->prefix);
It might be worth fixing the funny spacing on these lines, since all the affected lines are being replaced.
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if (cpu_has_vx()) { - size += nt_size(NT_S390_VXRS_HIGH, sizeof(sa->vxrs_high)); - size += nt_size(NT_S390_VXRS_LOW, sizeof(sa->vxrs_low)); + size += NT_SIZE(S390_VXRS_HIGH, sa->vxrs_high); + size += NT_SIZE(S390_VXRS_LOW, sa->vxrs_low); } return size;@@ -373,7 +357,7 @@ static void *nt_prpsinfo(void *ptr) memset(&prpsinfo, 0, sizeof(prpsinfo)); prpsinfo.pr_sname = 'R'; strcpy(prpsinfo.pr_fname, "vmlinux"); - return nt_init(ptr, NT_PRPSINFO, &prpsinfo, sizeof(prpsinfo)); + return NT_INIT(ptr, PRPSINFO, prpsinfo); } /*@@ -589,7 +573,7 @@ static size_t get_elfcorehdr_size(int phdr_count) /* PT_NOTES */ size += sizeof(Elf64_Phdr); /* nt_prpsinfo */ - size += nt_size(NT_PRPSINFO, sizeof(struct elf_prpsinfo)); + size += NT_SIZE(PRPSINFO, struct elf_prpsinfo); /* regsets */ size += get_cpu_cnt() * get_cpu_elf_notes_size(); /* nt_vmcoreinfo */
Otherwise, this looks sensible to me. Cheers ---Dave