From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pingfan Liu Date: Tue, 18 Jan 2022 15:48:11 +0800 Subject: [PATCHv4 3/4] arm64: read VA_BITS from kcore for 52-bits VA kernel In-Reply-To: <20220118074812.27702-1-piliu@redhat.com> References: <20220118074812.27702-1-piliu@redhat.com> Message-ID: <20220118074812.27702-4-piliu@redhat.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kexec@lists.infradead.org phys_to_virt() calculates virtual address. As a important factor, page_offset is excepted to be accurate. Since arm64 kernel exposes va_bits through vmcore, using it. Signed-off-by: Pingfan Liu Cc: Kairui Song Cc: Simon Horman Cc: Philipp Rudo To: kexec@lists.infradead.org --- kexec/arch/arm64/kexec-arm64.c | 34 ++++++++++++++++++++++++++++++---- util_lib/elf_info.c | 5 +++++ util_lib/include/elf_info.h | 1 + 3 files changed, 36 insertions(+), 4 deletions(-) diff --git a/kexec/arch/arm64/kexec-arm64.c b/kexec/arch/arm64/kexec-arm64.c index 33cc258..793799b 100644 --- a/kexec/arch/arm64/kexec-arm64.c +++ b/kexec/arch/arm64/kexec-arm64.c @@ -54,7 +54,7 @@ static bool try_read_phys_offset_from_kcore = false; /* Machine specific details. */ -static int va_bits; +static int va_bits = -1; static unsigned long page_offset; /* Global varables the core kexec routines expect. */ @@ -876,7 +876,18 @@ static inline void set_phys_offset(int64_t v, char *set_method) static int get_va_bits(void) { - unsigned long long stext_sym_addr = get_kernel_sym("_stext"); + unsigned long long stext_sym_addr; + + /* + * if already got from kcore + */ + if (va_bits != -1) + goto out; + + + /* For kernel older than v4.19 */ + fprintf(stderr, "Warning, can't get the VA_BITS from kcore\n"); + stext_sym_addr = get_kernel_sym("_stext"); if (stext_sym_addr == 0) { fprintf(stderr, "Can't get the symbol of _stext.\n"); @@ -900,6 +911,7 @@ static int get_va_bits(void) return -1; } +out: dbgprintf("va_bits : %d\n", va_bits); return 0; @@ -917,14 +929,27 @@ int get_page_offset(unsigned long *page_offset) if (ret < 0) return ret; - *page_offset = UINT64_MAX << (va_bits - 1); + if (va_bits < 52) + *page_offset = UINT64_MAX << (va_bits - 1); + else + *page_offset = UINT64_MAX << va_bits; + dbgprintf("page_offset : %lx\n", *page_offset); return 0; } +static void arm64_scan_vmcoreinfo(char *pos) +{ + const char *str; + + str = "NUMBER(VA_BITS)="; + if (memcmp(str, pos, strlen(str)) == 0) + va_bits = strtoul(pos + strlen(str), NULL, 10); +} + /** - * get_phys_offset_from_vmcoreinfo_pt_note - Helper for getting PHYS_OFFSET + * get_phys_offset_from_vmcoreinfo_pt_note - Helper for getting PHYS_OFFSET (and va_bits) * from VMCOREINFO note inside 'kcore'. */ @@ -937,6 +962,7 @@ static int get_phys_offset_from_vmcoreinfo_pt_note(long *phys_offset) return EFAILED; } + arch_scan_vmcoreinfo = arm64_scan_vmcoreinfo; ret = read_phys_offset_elf_kcore(fd, phys_offset); close(fd); diff --git a/util_lib/elf_info.c b/util_lib/elf_info.c index 5574c7f..d252eff 100644 --- a/util_lib/elf_info.c +++ b/util_lib/elf_info.c @@ -310,6 +310,8 @@ int get_pt_load(int idx, #define NOT_FOUND_LONG_VALUE (-1) +void (*arch_scan_vmcoreinfo)(char *pos); + void scan_vmcoreinfo(char *start, size_t size) { char *last = start + size - 1; @@ -551,6 +553,9 @@ void scan_vmcoreinfo(char *start, size_t size) } } + if (arch_scan_vmcoreinfo != NULL) + (*arch_scan_vmcoreinfo)(pos); + if (last_line) break; } diff --git a/util_lib/include/elf_info.h b/util_lib/include/elf_info.h index f550d86..fdf4c3d 100644 --- a/util_lib/include/elf_info.h +++ b/util_lib/include/elf_info.h @@ -31,5 +31,6 @@ int get_pt_load(int idx, int read_phys_offset_elf_kcore(int fd, long *phys_off); int read_elf(int fd); void dump_dmesg(int fd, void (*handler)(char*, unsigned int)); +extern void (*arch_scan_vmcoreinfo)(char *pos); #endif /* ELF_INFO_H */ -- 2.31.1