From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by bombadil.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lbhCu-00HLeC-5B for kexec@lists.infradead.org; Wed, 28 Apr 2021 10:14:13 +0000 Date: Wed, 28 Apr 2021 18:13:55 +0800 From: Baoquan He Subject: Re: [PATCH v5 13/13] kdump: Use vmlinux_build_id to simplify Message-ID: <20210428101355.GB8374@localhost.localdomain> References: <20210420215003.3510247-1-swboyd@chromium.org> <20210420215003.3510247-14-swboyd@chromium.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210420215003.3510247-14-swboyd@chromium.org> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Stephen Boyd Cc: Andrew Morton , linux-kernel@vger.kernel.org, Jiri Olsa , Alexei Starovoitov , Jessica Yu , Evan Green , Hsin-Yi Wang , Dave Young , Vivek Goyal , kexec@lists.infradead.org On 04/20/21 at 02:50pm, Stephen Boyd wrote: > We can use the vmlinux_build_id array here now instead of open coding > it. This mostly consolidates code. > > Cc: Jiri Olsa > Cc: Alexei Starovoitov > Cc: Jessica Yu > Cc: Evan Green > Cc: Hsin-Yi Wang > Cc: Dave Young > Cc: Baoquan He > Cc: Vivek Goyal > Cc: > Signed-off-by: Stephen Boyd > --- > include/linux/crash_core.h | 12 ++++----- > kernel/crash_core.c | 50 ++------------------------------------ > 2 files changed, 8 insertions(+), 54 deletions(-) > > diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h > index 206bde8308b2..de62a722431e 100644 > --- a/include/linux/crash_core.h > +++ b/include/linux/crash_core.h > @@ -38,8 +38,12 @@ phys_addr_t paddr_vmcoreinfo_note(void); > > #define VMCOREINFO_OSRELEASE(value) \ > vmcoreinfo_append_str("OSRELEASE=%s\n", value) > -#define VMCOREINFO_BUILD_ID(value) \ > - vmcoreinfo_append_str("BUILD-ID=%s\n", value) > +#define VMCOREINFO_BUILD_ID() \ > + ({ \ > + static_assert(sizeof(vmlinux_build_id) == 20); \ > + vmcoreinfo_append_str("BUILD-ID=%20phN\n", vmlinux_build_id); \ Since there has been static_assert at above, can we remove the magic number '20'? And I checked format_decode(), didn't find which type corresponds to 'N', could you tell? Other than these, this patch looks good to me, thanks for the effort. Thanks Baoquan > + }) > + > #define VMCOREINFO_PAGESIZE(value) \ > vmcoreinfo_append_str("PAGESIZE=%ld\n", value) > #define VMCOREINFO_SYMBOL(name) \ > @@ -69,10 +73,6 @@ extern unsigned char *vmcoreinfo_data; > extern size_t vmcoreinfo_size; > extern u32 *vmcoreinfo_note; > > -/* raw contents of kernel .notes section */ > -extern const void __start_notes __weak; > -extern const void __stop_notes __weak; > - > Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type, > void *data, size_t data_len); > void final_note(Elf_Word *buf); > diff --git a/kernel/crash_core.c b/kernel/crash_core.c > index 825284baaf46..29cc15398ee4 100644 > --- a/kernel/crash_core.c > +++ b/kernel/crash_core.c > @@ -4,6 +4,7 @@ > * Copyright (C) 2002-2004 Eric Biederman > */ > > +#include > #include > #include > #include > @@ -378,53 +379,6 @@ phys_addr_t __weak paddr_vmcoreinfo_note(void) > } > EXPORT_SYMBOL(paddr_vmcoreinfo_note); > > -#define NOTES_SIZE (&__stop_notes - &__start_notes) > -#define BUILD_ID_MAX SHA1_DIGEST_SIZE > -#define NT_GNU_BUILD_ID 3 > - > -struct elf_note_section { > - struct elf_note n_hdr; > - u8 n_data[]; > -}; > - > -/* > - * Add build ID from .notes section as generated by the GNU ld(1) > - * or LLVM lld(1) --build-id option. > - */ > -static void add_build_id_vmcoreinfo(void) > -{ > - char build_id[BUILD_ID_MAX * 2 + 1]; > - int n_remain = NOTES_SIZE; > - > - while (n_remain >= sizeof(struct elf_note)) { > - const struct elf_note_section *note_sec = > - &__start_notes + NOTES_SIZE - n_remain; > - const u32 n_namesz = note_sec->n_hdr.n_namesz; > - > - if (note_sec->n_hdr.n_type == NT_GNU_BUILD_ID && > - n_namesz != 0 && > - !strcmp((char *)¬e_sec->n_data[0], "GNU")) { > - if (note_sec->n_hdr.n_descsz <= BUILD_ID_MAX) { > - const u32 n_descsz = note_sec->n_hdr.n_descsz; > - const u8 *s = ¬e_sec->n_data[n_namesz]; > - > - s = PTR_ALIGN(s, 4); > - bin2hex(build_id, s, n_descsz); > - build_id[2 * n_descsz] = '\0'; > - VMCOREINFO_BUILD_ID(build_id); > - return; > - } > - pr_warn("Build ID is too large to include in vmcoreinfo: %u > %u\n", > - note_sec->n_hdr.n_descsz, > - BUILD_ID_MAX); > - return; > - } > - n_remain -= sizeof(struct elf_note) + > - ALIGN(note_sec->n_hdr.n_namesz, 4) + > - ALIGN(note_sec->n_hdr.n_descsz, 4); > - } > -} > - > static int __init crash_save_vmcoreinfo_init(void) > { > vmcoreinfo_data = (unsigned char *)get_zeroed_page(GFP_KERNEL); > @@ -443,7 +397,7 @@ static int __init crash_save_vmcoreinfo_init(void) > } > > VMCOREINFO_OSRELEASE(init_uts_ns.name.release); > - add_build_id_vmcoreinfo(); > + VMCOREINFO_BUILD_ID(); > VMCOREINFO_PAGESIZE(PAGE_SIZE); > > VMCOREINFO_SYMBOL(init_uts_ns); > -- > https://chromeos.dev > > > _______________________________________________ > kexec mailing list > kexec@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/kexec > _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec