On Wed, Mar 19, 2014 at 04:04:01PM +0800, WANG Chao wrote:
> command line size is restricted by kernel, sometimes memmap=exactmap has
> too many memory ranges to pass to cmdline. A better approach, to pass the
> memory ranges for crash kernel to boot into, is filling the memory
> ranges into E820.
>
> boot_params only got 128 slots for E820 map to fit in, when the number of
> memory map exceeds 128, use setup_data to pass the rest as extended E820
> memory map.
>
> kexec boot could also benefit from setup_data in case E820 memory map
> exceeds 128.
>
> Now this new approach becomes default instead of memmap=exactmap.
> saved_max_pfn users can specify --pass-memmap-cmdline to use the
> exactmap approach.
I think it is worth to also mention that kaslr enabled kernel does not
work with memmap=exactmap.
This patch in general looks good. Two minor nits below.
>
> Signed-off-by: WANG Chao <chaowang at redhat.com>
> Tested-by: Linn Crosetto <linn at hp.com>
> Reviewed-by: Linn Crosetto <linn at hp.com>
> ---
> kexec/arch/i386/crashdump-x86.c | 25 +++---
> kexec/arch/i386/crashdump-x86.h | 1 +
> kexec/arch/i386/x86-linux-setup.c | 171 +++++++++++++++++++++++++-------------
> 3 files changed, 130 insertions(+), 67 deletions(-)
>
> diff --git a/kexec/arch/i386/crashdump-x86.c b/kexec/arch/i386/crashdump-x86.c
> index c55a6b1..cb19e7d 100644
> --- a/kexec/arch/i386/crashdump-x86.c
> +++ b/kexec/arch/i386/crashdump-x86.c
> @@ -182,6 +182,8 @@ static int exclude_region(int *nr_ranges, uint64_t start, uint64_t end);
> struct memory_range crash_memory_range[CRASH_MAX_MEMORY_RANGES];
> int crash_memory_ranges;
>
> +int pass_memmap_cmdline;
> +
> /* Memory region reserved for storing panic kernel and other data. */
> #define CRASH_RESERVED_MEM_NR 8
> static struct memory_range crash_reserved_mem[CRASH_RESERVED_MEM_NR];
> @@ -947,20 +949,23 @@ int load_crashdump_segments(struct kexec_info *info, char* mod_cmdline,
> dbgprintf("Created elf header segment at 0x%lx\n", elfcorehdr);
> if (delete_memmap(crash_memory_range, &crash_memory_ranges, elfcorehdr, memsz) < 0)
> return -1;
> - cmdline_add_memmap(mod_cmdline, crash_memory_range);
> if (!bzImage_support_efi_boot)
> cmdline_add_efi(mod_cmdline);
> cmdline_add_elfcorehdr(mod_cmdline, elfcorehdr);
>
> - /* Inform second kernel about the presence of ACPI tables. */
> - for (i = 0; i < CRASH_MAX_MEMORY_RANGES; i++) {
> - unsigned long start, end;
> - if ( !( mem_range[i].type == RANGE_ACPI
> - || mem_range[i].type == RANGE_ACPI_NVS) )
> - continue;
> - start = mem_range[i].start;
> - end = mem_range[i].end;
> - cmdline_add_memmap_acpi(mod_cmdline, start, end);
> + pass_memmap_cmdline = arch_options.pass_memmap_cmdline;
> + if (pass_memmap_cmdline) {
> + cmdline_add_memmap(mod_cmdline, crash_memory_range);
> + /* Inform second kernel about the presence of ACPI tables. */
> + for (i = 0; i < CRASH_MAX_MEMORY_RANGES; i++) {
> + unsigned long start, end;
> + if ( !( mem_range[i].type == RANGE_ACPI
> + || mem_range[i].type == RANGE_ACPI_NVS) )
> + continue;
> + start = mem_range[i].start;
> + end = mem_range[i].end;
> + cmdline_add_memmap_acpi(mod_cmdline, start, end);
> + }
> }
>
> return 0;
> diff --git a/kexec/arch/i386/crashdump-x86.h b/kexec/arch/i386/crashdump-x86.h
> index 633ee0e..e68b626 100644
> --- a/kexec/arch/i386/crashdump-x86.h
> +++ b/kexec/arch/i386/crashdump-x86.h
> @@ -30,5 +30,6 @@ int load_crashdump_segments(struct kexec_info *info, char *mod_cmdline,
>
> extern struct memory_range crash_memory_range[CRASH_MAX_MEMORY_RANGES];
> extern int crash_memory_ranges;
> +extern int pass_memmap_cmdline;
>
> #endif /* CRASHDUMP_X86_H */
> diff --git a/kexec/arch/i386/x86-linux-setup.c b/kexec/arch/i386/x86-linux-setup.c
> index 5884f4d..e8865e1 100644
> --- a/kexec/arch/i386/x86-linux-setup.c
> +++ b/kexec/arch/i386/x86-linux-setup.c
> @@ -35,8 +35,7 @@
> #include "kexec-x86.h"
> #include "x86-linux-setup.h"
> #include "../../kexec/kexec-syscall.h"
> -
> -#define SETUP_EFI 4
> +#include "crashdump-x86.h"
>
> void init_linux_parameters(struct x86_linux_param_header *real_mode)
> {
> @@ -502,6 +501,11 @@ struct efi_setup_data {
> struct setup_data {
> uint64_t next;
> uint32_t type;
> +#define SETUP_NONE 0
> +#define SETUP_E820_EXT 1
> +#define SETUP_DTB 2
> +#define SETUP_PCI 3
> +#define SETUP_EFI 4
> uint32_t len;
> uint8_t data[0];
> } __attribute__((packed));
> @@ -602,6 +606,17 @@ struct efi_info {
> uint32_t efi_memmap_hi;
> };
>
> +static void add_setup_data(struct kexec_info *info,
> + struct x86_linux_param_header *real_mode,
> + struct setup_data *sd)
> +{
What is setup_data? A little comment above function will make it easy
to read. Is it that list of elements which contains extra memory map
entries?
> + int sdsize = sizeof(struct setup_data) + sd->len;
> +
> + sd->next = real_mode->setup_data;
> + real_mode->setup_data = add_buffer(info, sd, sdsize, sdsize, getpagesize(),
> + 0x100000, ULONG_MAX, INT_MAX);
> +}
> +
> /*
> * setup_efi_data will collect below data and pass them to 2nd kernel.
> * 1) SMBIOS, fw_vendor, runtime, config_table, they are passed via x86
> @@ -611,11 +626,11 @@ struct efi_info {
> static int setup_efi_data(struct kexec_info *info,
> struct x86_linux_param_header *real_mode)
> {
> - int64_t setup_data_paddr, memmap_paddr;
> + int64_t memmap_paddr;
> struct setup_data *sd;
> struct efi_setup_data *esd;
> struct efi_mem_descriptor *maps;
> - int nr_maps, size, sdsize, ret = 0;
> + int nr_maps, size, ret = 0;
> struct efi_info *ei = (struct efi_info *)real_mode->efi_info;
>
> ret = access("/sys/firmware/efi/systab", F_OK);
> @@ -648,10 +663,8 @@ static int setup_efi_data(struct kexec_info *info,
> sd->len = sizeof(*esd);
> memcpy(sd->data, esd, sizeof(*esd));
> free(esd);
> - sdsize = sd->len + sizeof(struct setup_data);
> - setup_data_paddr = add_buffer(info, sd, sdsize, sdsize, getpagesize(),
> - 0x100000, ULONG_MAX, INT_MAX);
> - real_mode->setup_data = setup_data_paddr;
> +
> + add_setup_data(info, real_mode, sd);
>
> size = nr_maps * sizeof(struct efi_mem_descriptor);
> memmap_paddr = add_buffer(info, maps, size, size, getpagesize(),
> @@ -669,6 +682,98 @@ out:
> return ret;
> }
>
> +static void add_e820_map_from_mr(struct x86_linux_param_header *real_mode,
> + struct e820entry *e820, struct memory_range *range, int nr_range)
> +{
> + int i;
> +
> + for (i = 0; i < nr_range; i++) {
> + e820[i].addr = range[i].start;
> + e820[i].size = range[i].end - range[i].start;
> + switch (range[i].type) {
> + case RANGE_RAM:
> + e820[i].type = E820_RAM;
> + break;
> + case RANGE_ACPI:
> + e820[i].type = E820_ACPI;
> + break;
> + case RANGE_ACPI_NVS:
> + e820[i].type = E820_NVS;
> + break;
> + default:
> + case RANGE_RESERVED:
> + e820[i].type = E820_RESERVED;
> + break;
> + }
> + dbgprintf("%016lx-%016lx (%d)\n",
> + e820[i].addr,
> + e820[i].addr + e820[i].size - 1,
> + e820[i].type);
> +
> + if (range[i].type != RANGE_RAM)
> + continue;
> + if ((range[i].start <= 0x100000) && range[i].end > 0x100000) {
> + unsigned long long mem_k = (range[i].end >> 10) - (0x100000 >> 10);
> + real_mode->ext_mem_k = mem_k;
> + real_mode->alt_mem_k = mem_k;
> + if (mem_k > 0xfc00) {
> + real_mode->ext_mem_k = 0xfc00; /* 64M */
> + }
> + if (mem_k > 0xffffffff) {
> + real_mode->alt_mem_k = 0xffffffff;
> + }
> + }
> + }
> +}
> +
> +static void setup_e820_ext(struct kexec_info *info, struct x86_linux_param_header *real_mode,
> + struct memory_range *range, int nr_range)
> +{
> + struct setup_data *sd;
> + struct e820entry *e820;
> + int nr_range_ext;
> +
> + nr_range_ext = nr_range - E820MAX;
> + sd = xmalloc(sizeof(struct setup_data) + nr_range_ext * sizeof(struct e820entry));
> + sd->next = 0;
> + sd->len = nr_range_ext * sizeof(struct e820entry);
> + sd->type = SETUP_E820_EXT;
> +
> + e820 = (struct e820entry *) sd->data;
> + dbgprintf("Extended E820 via setup_data:\n");
> + add_e820_map_from_mr(real_mode, e820, range + E820MAX, nr_range_ext);
> + add_setup_data(info, real_mode, sd);
> +}
> +
> +static void setup_e820(struct kexec_info *info, struct x86_linux_param_header *real_mode)
> +{
> + struct memory_range *range;
> + int nr_range, nr_range_saved;
> +
> +
> + if (info->kexec_flags & KEXEC_ON_CRASH && !pass_memmap_cmdline) {
> + range = crash_memory_range;
> + nr_range = crash_memory_ranges;
You know what, it might be a good idea to store the pointer to
crash_memory_range in kexec_info too, (like memory_range and
memory_ranges).
> + } else {
> + range = info->memory_range;
> + nr_range = info->memory_ranges;
> + }
> +
> + nr_range_saved = nr_range;
> + if (nr_range > E820MAX) {
> + nr_range = E820MAX;
> + }
> +
> + real_mode->e820_map_nr = nr_range;
> + dbgprintf("E820 memmap:\n");
> + add_e820_map_from_mr(real_mode, real_mode->e820_map, range, nr_range);
> +
> + if (nr_range_saved > E820MAX) {
> + dbgprintf("extra E820 memmap are passed via setup_data\n");
> + setup_e820_ext(info, real_mode, range, nr_range_saved);
> + }
> +}
> +
> static int
> get_efi_mem_desc_version(struct x86_linux_param_header *real_mode)
> {
> @@ -702,10 +807,6 @@ static void setup_efi_info(struct kexec_info *info,
> void setup_linux_system_parameters(struct kexec_info *info,
> struct x86_linux_param_header *real_mode)
> {
> - /* Fill in information the BIOS would usually provide */
> - struct memory_range *range;
> - int i, ranges;
> -
> /* get subarch from running kernel */
> setup_subarch(real_mode);
> if (bzImage_support_efi_boot)
> @@ -746,51 +847,7 @@ void setup_linux_system_parameters(struct kexec_info *info,
> /* another safe default */
> real_mode->aux_device_info = 0;
>
> - range = info->memory_range;
> - ranges = info->memory_ranges;
> - if (ranges > E820MAX) {
> - if (!(info->kexec_flags & KEXEC_ON_CRASH))
> - /*
> - * this e820 not used for capture kernel, see
> - * do_bzImage_load()
> - */
> - fprintf(stderr,
> - "Too many memory ranges, truncating...\n");
> - ranges = E820MAX;
> - }
> - real_mode->e820_map_nr = ranges;
> - for(i = 0; i < ranges; i++) {
> - real_mode->e820_map[i].addr = range[i].start;
> - real_mode->e820_map[i].size = range[i].end - range[i].start;
> - switch (range[i].type) {
> - case RANGE_RAM:
> - real_mode->e820_map[i].type = E820_RAM;
> - break;
> - case RANGE_ACPI:
> - real_mode->e820_map[i].type = E820_ACPI;
> - break;
> - case RANGE_ACPI_NVS:
> - real_mode->e820_map[i].type = E820_NVS;
> - break;
> - default:
> - case RANGE_RESERVED:
> - real_mode->e820_map[i].type = E820_RESERVED;
> - break;
> - }
> - if (range[i].type != RANGE_RAM)
> - continue;
> - if ((range[i].start <= 0x100000) && range[i].end > 0x100000) {
> - unsigned long long mem_k = (range[i].end >> 10) - (0x100000 >> 10);
> - real_mode->ext_mem_k = mem_k;
> - real_mode->alt_mem_k = mem_k;
> - if (mem_k > 0xfc00) {
> - real_mode->ext_mem_k = 0xfc00; /* 64M */
> - }
> - if (mem_k > 0xffffffff) {
> - real_mode->alt_mem_k = 0xffffffff;
> - }
> - }
> - }
> + setup_e820(info, real_mode);
>
> /* fill the EDD information */
> setup_edd_info(real_mode);
> --
> 1.8.5.3
>
>
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