| Message ID | 20180227044814.24808-6-takahiro.akashi@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 02/27/18 at 01:48pm, AKASHI Takahiro wrote: > While CRASH_MAX_RANGES (== 16) seems to be good enough, fixed-number > array is not a good idea in general. > > In this patch, size of crash_mem buffer is calculated as before and > the buffer is now dynamically allocated. This change also allows removing > crash_elf_data structure. > > Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> > Cc: Dave Young <dyoung@redhat.com> > Cc: Vivek Goyal <vgoyal@redhat.com> > Cc: Baoquan He <bhe@redhat.com> > --- > arch/x86/kernel/crash.c | 80 ++++++++++++++++++------------------------------- > 1 file changed, 29 insertions(+), 51 deletions(-) > > diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c > index 913fd8021f8a..bfc37ad20d4a 100644 > --- a/arch/x86/kernel/crash.c > +++ b/arch/x86/kernel/crash.c > @@ -41,32 +41,14 @@ > /* Alignment required for elf header segment */ > #define ELF_CORE_HEADER_ALIGN 4096 > > -/* This primarily represents number of split ranges due to exclusion */ > -#define CRASH_MAX_RANGES 16 > - > struct crash_mem_range { > u64 start, end; > }; > > struct crash_mem { > - unsigned int nr_ranges; > - struct crash_mem_range ranges[CRASH_MAX_RANGES]; > -}; > - > -/* Misc data about ram ranges needed to prepare elf headers */ > -struct crash_elf_data { > - struct kimage *image; > - /* > - * Total number of ram ranges we have after various adjustments for > - * crash reserved region, etc. > - */ > unsigned int max_nr_ranges; > - > - /* Pointer to elf header */ > - void *ehdr; > - /* Pointer to next phdr */ > - void *bufp; > - struct crash_mem mem; > + unsigned int nr_ranges; > + struct crash_mem_range ranges[0]; > }; > > /* Used while preparing memory map entries for second kernel */ > @@ -217,26 +199,29 @@ static int get_nr_ram_ranges_callback(struct resource *res, void *arg) > return 0; > } > > - > /* Gather all the required information to prepare elf headers for ram regions */ > -static void fill_up_crash_elf_data(struct crash_elf_data *ced, > - struct kimage *image) > +static struct crash_mem *fill_up_crash_elf_data(void) > { > unsigned int nr_ranges = 0; > - > - ced->image = image; > + struct crash_mem *cmem; > > walk_system_ram_res(0, -1, &nr_ranges, > get_nr_ram_ranges_callback); I know it is probably not possible fail here, but for safe we can check if nr_ranges == 0 > > - ced->max_nr_ranges = nr_ranges; > + /* > + * Exclusion of crash region and/or crashk_low_res may cause > + * another range split. So add extra two slots here. > + */ > + nr_ranges += 2; > + cmem = vmalloc(sizeof(struct crash_mem) + > + sizeof(struct crash_mem_range) * nr_ranges); > + if (!cmem) > + return NULL; vzalloc will be better. > > - /* Exclusion of crash region could split memory ranges */ > - ced->max_nr_ranges++; > + cmem->max_nr_ranges = nr_ranges; > + cmem->nr_ranges = 0; > > - /* If crashk_low_res is not 0, another range split possible */ > - if (crashk_low_res.end) > - ced->max_nr_ranges++; > + return cmem; > } > > static int exclude_mem_range(struct crash_mem *mem, > @@ -293,10 +278,8 @@ static int exclude_mem_range(struct crash_mem *mem, > return 0; > > /* Split happened */ > - if (i == CRASH_MAX_RANGES - 1) { > - pr_err("Too many crash ranges after split\n"); > + if (i == mem->max_nr_ranges - 1) > return -ENOMEM; > - } > > /* Location where new range should go */ > j = i + 1; > @@ -314,11 +297,10 @@ static int exclude_mem_range(struct crash_mem *mem, > > /* > * Look for any unwanted ranges between mstart, mend and remove them. This > - * might lead to split and split ranges are put in ced->mem.ranges[] array > + * might lead to split and split ranges are put in cmem->ranges[] array > */ > -static int elf_header_exclude_ranges(struct crash_elf_data *ced) > +static int elf_header_exclude_ranges(struct crash_mem *cmem) > { > - struct crash_mem *cmem = &ced->mem; > int ret = 0; > > /* Exclude crashkernel region */ > @@ -337,8 +319,7 @@ static int elf_header_exclude_ranges(struct crash_elf_data *ced) > > static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg) > { > - struct crash_elf_data *ced = arg; > - struct crash_mem *cmem = &ced->mem; > + struct crash_mem *cmem = arg; > > cmem->ranges[cmem->nr_ranges].start = res->start; > cmem->ranges[cmem->nr_ranges].end = res->end; > @@ -347,7 +328,7 @@ static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg) > return 0; > } > > -static int prepare_elf64_headers(struct crash_elf_data *ced, int kernel_map, > +static int prepare_elf64_headers(struct crash_mem *cmem, int kernel_map, > void **addr, unsigned long *sz) > { > Elf64_Ehdr *ehdr; > @@ -356,12 +337,11 @@ static int prepare_elf64_headers(struct crash_elf_data *ced, int kernel_map, > unsigned char *buf, *bufp; > unsigned int cpu, i; > unsigned long long notes_addr; > - struct crash_mem *cmem = &ced->mem; > unsigned long mstart, mend; > > /* extra phdr for vmcoreinfo elf note */ > nr_phdr = nr_cpus + 1; > - nr_phdr += ced->max_nr_ranges; > + nr_phdr += cmem->nr_ranges; > > /* > * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping > @@ -455,29 +435,27 @@ static int prepare_elf64_headers(struct crash_elf_data *ced, int kernel_map, > static int prepare_elf_headers(struct kimage *image, void **addr, > unsigned long *sz) > { > - struct crash_elf_data *ced; > + struct crash_mem *cmem; > Elf64_Ehdr *ehdr; > Elf64_Phdr *phdr; > int ret, i; > > - ced = kzalloc(sizeof(*ced), GFP_KERNEL); > - if (!ced) > + cmem = fill_up_crash_elf_data(); > + if (!cmem) > return -ENOMEM; > > - fill_up_crash_elf_data(ced, image); > - > - ret = walk_system_ram_res(0, -1, ced, > + ret = walk_system_ram_res(0, -1, cmem, > prepare_elf64_ram_headers_callback); > if (ret) > goto out; > > /* Exclude unwanted mem ranges */ > - ret = elf_header_exclude_ranges(ced); > + ret = elf_header_exclude_ranges(cmem); > if (ret) > goto out; > > /* By default prepare 64bit headers */ > - ret = prepare_elf64_headers(ced, > + ret = prepare_elf64_headers(cmem, > (int)IS_ENABLED(CONFIG_X86_64), addr, sz); > if (ret) > goto out; > @@ -496,7 +474,7 @@ static int prepare_elf_headers(struct kimage *image, void **addr, > break; > } > out: > - kfree(ced); > + vfree(cmem); > return ret; > } > > -- > 2.16.2 > Thanks Dave
On Fri, Mar 02, 2018 at 01:31:53PM +0800, Dave Young wrote: > On 02/27/18 at 01:48pm, AKASHI Takahiro wrote: > > While CRASH_MAX_RANGES (== 16) seems to be good enough, fixed-number > > array is not a good idea in general. > > > > In this patch, size of crash_mem buffer is calculated as before and > > the buffer is now dynamically allocated. This change also allows removing > > crash_elf_data structure. > > > > Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> > > Cc: Dave Young <dyoung@redhat.com> > > Cc: Vivek Goyal <vgoyal@redhat.com> > > Cc: Baoquan He <bhe@redhat.com> > > --- > > arch/x86/kernel/crash.c | 80 ++++++++++++++++++------------------------------- > > 1 file changed, 29 insertions(+), 51 deletions(-) > > > > diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c > > index 913fd8021f8a..bfc37ad20d4a 100644 > > --- a/arch/x86/kernel/crash.c > > +++ b/arch/x86/kernel/crash.c > > @@ -41,32 +41,14 @@ > > /* Alignment required for elf header segment */ > > #define ELF_CORE_HEADER_ALIGN 4096 > > > > -/* This primarily represents number of split ranges due to exclusion */ > > -#define CRASH_MAX_RANGES 16 > > - > > struct crash_mem_range { > > u64 start, end; > > }; > > > > struct crash_mem { > > - unsigned int nr_ranges; > > - struct crash_mem_range ranges[CRASH_MAX_RANGES]; > > -}; > > - > > -/* Misc data about ram ranges needed to prepare elf headers */ > > -struct crash_elf_data { > > - struct kimage *image; > > - /* > > - * Total number of ram ranges we have after various adjustments for > > - * crash reserved region, etc. > > - */ > > unsigned int max_nr_ranges; > > - > > - /* Pointer to elf header */ > > - void *ehdr; > > - /* Pointer to next phdr */ > > - void *bufp; > > - struct crash_mem mem; > > + unsigned int nr_ranges; > > + struct crash_mem_range ranges[0]; > > }; > > > > /* Used while preparing memory map entries for second kernel */ > > @@ -217,26 +199,29 @@ static int get_nr_ram_ranges_callback(struct resource *res, void *arg) > > return 0; > > } > > > > - > > /* Gather all the required information to prepare elf headers for ram regions */ > > -static void fill_up_crash_elf_data(struct crash_elf_data *ced, > > - struct kimage *image) > > +static struct crash_mem *fill_up_crash_elf_data(void) > > { > > unsigned int nr_ranges = 0; > > - > > - ced->image = image; > > + struct crash_mem *cmem; > > > > walk_system_ram_res(0, -1, &nr_ranges, > > get_nr_ram_ranges_callback); > > I know it is probably not possible fail here, but for safe we can check > if nr_ranges == 0 OK. > > > > - ced->max_nr_ranges = nr_ranges; > > + /* > > + * Exclusion of crash region and/or crashk_low_res may cause > > + * another range split. So add extra two slots here. > > + */ > > + nr_ranges += 2; > > + cmem = vmalloc(sizeof(struct crash_mem) + > > + sizeof(struct crash_mem_range) * nr_ranges); > > + if (!cmem) > > + return NULL; > > vzalloc will be better. Sure. -Takahiro AKASHI > > > > - /* Exclusion of crash region could split memory ranges */ > > - ced->max_nr_ranges++; > > + cmem->max_nr_ranges = nr_ranges; > > + cmem->nr_ranges = 0; > > > > - /* If crashk_low_res is not 0, another range split possible */ > > - if (crashk_low_res.end) > > - ced->max_nr_ranges++; > > + return cmem; > > } > > > > static int exclude_mem_range(struct crash_mem *mem, > > @@ -293,10 +278,8 @@ static int exclude_mem_range(struct crash_mem *mem, > > return 0; > > > > /* Split happened */ > > - if (i == CRASH_MAX_RANGES - 1) { > > - pr_err("Too many crash ranges after split\n"); > > + if (i == mem->max_nr_ranges - 1) > > return -ENOMEM; > > - } > > > > /* Location where new range should go */ > > j = i + 1; > > @@ -314,11 +297,10 @@ static int exclude_mem_range(struct crash_mem *mem, > > > > /* > > * Look for any unwanted ranges between mstart, mend and remove them. This > > - * might lead to split and split ranges are put in ced->mem.ranges[] array > > + * might lead to split and split ranges are put in cmem->ranges[] array > > */ > > -static int elf_header_exclude_ranges(struct crash_elf_data *ced) > > +static int elf_header_exclude_ranges(struct crash_mem *cmem) > > { > > - struct crash_mem *cmem = &ced->mem; > > int ret = 0; > > > > /* Exclude crashkernel region */ > > @@ -337,8 +319,7 @@ static int elf_header_exclude_ranges(struct crash_elf_data *ced) > > > > static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg) > > { > > - struct crash_elf_data *ced = arg; > > - struct crash_mem *cmem = &ced->mem; > > + struct crash_mem *cmem = arg; > > > > cmem->ranges[cmem->nr_ranges].start = res->start; > > cmem->ranges[cmem->nr_ranges].end = res->end; > > @@ -347,7 +328,7 @@ static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg) > > return 0; > > } > > > > -static int prepare_elf64_headers(struct crash_elf_data *ced, int kernel_map, > > +static int prepare_elf64_headers(struct crash_mem *cmem, int kernel_map, > > void **addr, unsigned long *sz) > > { > > Elf64_Ehdr *ehdr; > > @@ -356,12 +337,11 @@ static int prepare_elf64_headers(struct crash_elf_data *ced, int kernel_map, > > unsigned char *buf, *bufp; > > unsigned int cpu, i; > > unsigned long long notes_addr; > > - struct crash_mem *cmem = &ced->mem; > > unsigned long mstart, mend; > > > > /* extra phdr for vmcoreinfo elf note */ > > nr_phdr = nr_cpus + 1; > > - nr_phdr += ced->max_nr_ranges; > > + nr_phdr += cmem->nr_ranges; > > > > /* > > * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping > > @@ -455,29 +435,27 @@ static int prepare_elf64_headers(struct crash_elf_data *ced, int kernel_map, > > static int prepare_elf_headers(struct kimage *image, void **addr, > > unsigned long *sz) > > { > > - struct crash_elf_data *ced; > > + struct crash_mem *cmem; > > Elf64_Ehdr *ehdr; > > Elf64_Phdr *phdr; > > int ret, i; > > > > - ced = kzalloc(sizeof(*ced), GFP_KERNEL); > > - if (!ced) > > + cmem = fill_up_crash_elf_data(); > > + if (!cmem) > > return -ENOMEM; > > > > - fill_up_crash_elf_data(ced, image); > > - > > - ret = walk_system_ram_res(0, -1, ced, > > + ret = walk_system_ram_res(0, -1, cmem, > > prepare_elf64_ram_headers_callback); > > if (ret) > > goto out; > > > > /* Exclude unwanted mem ranges */ > > - ret = elf_header_exclude_ranges(ced); > > + ret = elf_header_exclude_ranges(cmem); > > if (ret) > > goto out; > > > > /* By default prepare 64bit headers */ > > - ret = prepare_elf64_headers(ced, > > + ret = prepare_elf64_headers(cmem, > > (int)IS_ENABLED(CONFIG_X86_64), addr, sz); > > if (ret) > > goto out; > > @@ -496,7 +474,7 @@ static int prepare_elf_headers(struct kimage *image, void **addr, > > break; > > } > > out: > > - kfree(ced); > > + vfree(cmem); > > return ret; > > } > > > > -- > > 2.16.2 > > > > Thanks > Dave
diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c index 913fd8021f8a..bfc37ad20d4a 100644 --- a/arch/x86/kernel/crash.c +++ b/arch/x86/kernel/crash.c @@ -41,32 +41,14 @@ /* Alignment required for elf header segment */ #define ELF_CORE_HEADER_ALIGN 4096 -/* This primarily represents number of split ranges due to exclusion */ -#define CRASH_MAX_RANGES 16 - struct crash_mem_range { u64 start, end; }; struct crash_mem { - unsigned int nr_ranges; - struct crash_mem_range ranges[CRASH_MAX_RANGES]; -}; - -/* Misc data about ram ranges needed to prepare elf headers */ -struct crash_elf_data { - struct kimage *image; - /* - * Total number of ram ranges we have after various adjustments for - * crash reserved region, etc. - */ unsigned int max_nr_ranges; - - /* Pointer to elf header */ - void *ehdr; - /* Pointer to next phdr */ - void *bufp; - struct crash_mem mem; + unsigned int nr_ranges; + struct crash_mem_range ranges[0]; }; /* Used while preparing memory map entries for second kernel */ @@ -217,26 +199,29 @@ static int get_nr_ram_ranges_callback(struct resource *res, void *arg) return 0; } - /* Gather all the required information to prepare elf headers for ram regions */ -static void fill_up_crash_elf_data(struct crash_elf_data *ced, - struct kimage *image) +static struct crash_mem *fill_up_crash_elf_data(void) { unsigned int nr_ranges = 0; - - ced->image = image; + struct crash_mem *cmem; walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback); - ced->max_nr_ranges = nr_ranges; + /* + * Exclusion of crash region and/or crashk_low_res may cause + * another range split. So add extra two slots here. + */ + nr_ranges += 2; + cmem = vmalloc(sizeof(struct crash_mem) + + sizeof(struct crash_mem_range) * nr_ranges); + if (!cmem) + return NULL; - /* Exclusion of crash region could split memory ranges */ - ced->max_nr_ranges++; + cmem->max_nr_ranges = nr_ranges; + cmem->nr_ranges = 0; - /* If crashk_low_res is not 0, another range split possible */ - if (crashk_low_res.end) - ced->max_nr_ranges++; + return cmem; } static int exclude_mem_range(struct crash_mem *mem, @@ -293,10 +278,8 @@ static int exclude_mem_range(struct crash_mem *mem, return 0; /* Split happened */ - if (i == CRASH_MAX_RANGES - 1) { - pr_err("Too many crash ranges after split\n"); + if (i == mem->max_nr_ranges - 1) return -ENOMEM; - } /* Location where new range should go */ j = i + 1; @@ -314,11 +297,10 @@ static int exclude_mem_range(struct crash_mem *mem, /* * Look for any unwanted ranges between mstart, mend and remove them. This - * might lead to split and split ranges are put in ced->mem.ranges[] array + * might lead to split and split ranges are put in cmem->ranges[] array */ -static int elf_header_exclude_ranges(struct crash_elf_data *ced) +static int elf_header_exclude_ranges(struct crash_mem *cmem) { - struct crash_mem *cmem = &ced->mem; int ret = 0; /* Exclude crashkernel region */ @@ -337,8 +319,7 @@ static int elf_header_exclude_ranges(struct crash_elf_data *ced) static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg) { - struct crash_elf_data *ced = arg; - struct crash_mem *cmem = &ced->mem; + struct crash_mem *cmem = arg; cmem->ranges[cmem->nr_ranges].start = res->start; cmem->ranges[cmem->nr_ranges].end = res->end; @@ -347,7 +328,7 @@ static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg) return 0; } -static int prepare_elf64_headers(struct crash_elf_data *ced, int kernel_map, +static int prepare_elf64_headers(struct crash_mem *cmem, int kernel_map, void **addr, unsigned long *sz) { Elf64_Ehdr *ehdr; @@ -356,12 +337,11 @@ static int prepare_elf64_headers(struct crash_elf_data *ced, int kernel_map, unsigned char *buf, *bufp; unsigned int cpu, i; unsigned long long notes_addr; - struct crash_mem *cmem = &ced->mem; unsigned long mstart, mend; /* extra phdr for vmcoreinfo elf note */ nr_phdr = nr_cpus + 1; - nr_phdr += ced->max_nr_ranges; + nr_phdr += cmem->nr_ranges; /* * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping @@ -455,29 +435,27 @@ static int prepare_elf64_headers(struct crash_elf_data *ced, int kernel_map, static int prepare_elf_headers(struct kimage *image, void **addr, unsigned long *sz) { - struct crash_elf_data *ced; + struct crash_mem *cmem; Elf64_Ehdr *ehdr; Elf64_Phdr *phdr; int ret, i; - ced = kzalloc(sizeof(*ced), GFP_KERNEL); - if (!ced) + cmem = fill_up_crash_elf_data(); + if (!cmem) return -ENOMEM; - fill_up_crash_elf_data(ced, image); - - ret = walk_system_ram_res(0, -1, ced, + ret = walk_system_ram_res(0, -1, cmem, prepare_elf64_ram_headers_callback); if (ret) goto out; /* Exclude unwanted mem ranges */ - ret = elf_header_exclude_ranges(ced); + ret = elf_header_exclude_ranges(cmem); if (ret) goto out; /* By default prepare 64bit headers */ - ret = prepare_elf64_headers(ced, + ret = prepare_elf64_headers(cmem, (int)IS_ENABLED(CONFIG_X86_64), addr, sz); if (ret) goto out; @@ -496,7 +474,7 @@ static int prepare_elf_headers(struct kimage *image, void **addr, break; } out: - kfree(ced); + vfree(cmem); return ret; }
While CRASH_MAX_RANGES (== 16) seems to be good enough, fixed-number array is not a good idea in general. In this patch, size of crash_mem buffer is calculated as before and the buffer is now dynamically allocated. This change also allows removing crash_elf_data structure. Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> Cc: Dave Young <dyoung@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Baoquan He <bhe@redhat.com> --- arch/x86/kernel/crash.c | 80 ++++++++++++++++++------------------------------- 1 file changed, 29 insertions(+), 51 deletions(-)