AcoSail/kernel_optimize_test
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Merge branch 'x86-kdump-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

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Pull x86 kdump updates from Ingo Molnar:
 "This solves a kdump artifact where encrypted memory contents are
  dumped, instead of unencrypted ones.

  The solution also happens to simplify the kdump code, to everyone's
  delight"

* 'x86-kdump-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/crash: Align function arguments on opening braces
  x86/kdump: Remove the backup region handling
  x86/kdump: Always reserve the low 1M when the crashkernel option is specified
  x86/crash: Add a forward declaration of struct kimage
This commit is contained in:
Linus Torvalds 2019-11-26 09:48:19 -08:00
commit 24ee25a6da
7 changed files with 46 additions and 178 deletions
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8
arch/x86/include/asm/crash.h
View File

@ -2,9 +2,17 @@
#ifndef _ASM_X86_CRASH_H
#define _ASM_X86_CRASH_H
struct kimage;
int crash_load_segments(struct kimage *image);
int crash_setup_memmap_entries(struct kimage *image,
struct boot_params *params);
void crash_smp_send_stop(void);
#ifdef CONFIG_KEXEC_CORE
void __init crash_reserve_low_1M(void);
#else
static inline void __init crash_reserve_low_1M(void) { }
#endif
#endif /* _ASM_X86_CRASH_H */

10
arch/x86/include/asm/kexec.h
View File

@ -66,10 +66,6 @@ struct kimage;
# define KEXEC_ARCH KEXEC_ARCH_X86_64
#endif
/* Memory to backup during crash kdump */
#define KEXEC_BACKUP_SRC_START (0UL)
#define KEXEC_BACKUP_SRC_END (640 * 1024UL - 1) /* 640K */
/*
* This function is responsible for capturing register states if coming
* via panic otherwise just fix up the ss and sp if coming via kernel
@ -154,12 +150,6 @@ struct kimage_arch {
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
/* Details of backup region */
unsigned long backup_src_start;
unsigned long backup_src_sz;
/* Physical address of backup segment */
unsigned long backup_load_addr;
/* Core ELF header buffer */
void *elf_headers;

10
arch/x86/include/asm/purgatory.h
View File

@ -6,16 +6,6 @@
#include <linux/purgatory.h>
extern void purgatory(void);
/*
* These forward declarations serve two purposes:
*
* 1) Make sparse happy when checking arch/purgatory
* 2) Document that these are required to be global so the symbol
* lookup in kexec works
*/
extern unsigned long purgatory_backup_dest;
extern unsigned long purgatory_backup_src;
extern unsigned long purgatory_backup_sz;
#endif /* __ASSEMBLY__ */
#endif /* _ASM_PURGATORY_H */

128
arch/x86/kernel/crash.c
View File

@ -24,6 +24,7 @@
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/memblock.h>
#include <asm/processor.h>
#include <asm/hardirq.h>
@ -39,6 +40,7 @@
#include <asm/virtext.h>
#include <asm/intel_pt.h>
#include <asm/crash.h>
#include <asm/cmdline.h>
/* Used while preparing memory map entries for second kernel */
struct crash_memmap_data {
@ -68,6 +70,19 @@ static inline void cpu_crash_vmclear_loaded_vmcss(void)
rcu_read_unlock();
}
/*
* When the crashkernel option is specified, only use the low
* 1M for the real mode trampoline.
*/
void __init crash_reserve_low_1M(void)
{
if (cmdline_find_option(boot_command_line, "crashkernel", NULL, 0) < 0)
return;
memblock_reserve(0, 1<<20);
pr_info("Reserving the low 1M of memory for crashkernel\n");
}
#if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
static void kdump_nmi_callback(int cpu, struct pt_regs *regs)
@ -173,8 +188,6 @@ void native_machine_crash_shutdown(struct pt_regs *regs)
#ifdef CONFIG_KEXEC_FILE
static unsigned long crash_zero_bytes;
static int get_nr_ram_ranges_callback(struct resource *res, void *arg)
{
unsigned int *nr_ranges = arg;
@ -189,8 +202,7 @@ static struct crash_mem *fill_up_crash_elf_data(void)
unsigned int nr_ranges = 0;
struct crash_mem *cmem;
walk_system_ram_res(0, -1, &nr_ranges,
get_nr_ram_ranges_callback);
walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback);
if (!nr_ranges)
return NULL;
@ -217,15 +229,19 @@ static int elf_header_exclude_ranges(struct crash_mem *cmem)
{
int ret = 0;
/* Exclude the low 1M because it is always reserved */
ret = crash_exclude_mem_range(cmem, 0, 1<<20);
if (ret)
return ret;
/* Exclude crashkernel region */
ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
if (ret)
return ret;
if (crashk_low_res.end) {
if (crashk_low_res.end)
ret = crash_exclude_mem_range(cmem, crashk_low_res.start,
crashk_low_res.end);
}
crashk_low_res.end);
return ret;
}
@ -246,16 +262,13 @@ static int prepare_elf_headers(struct kimage *image, void **addr,
unsigned long *sz)
{
struct crash_mem *cmem;
Elf64_Ehdr *ehdr;
Elf64_Phdr *phdr;
int ret, i;
int ret;
cmem = fill_up_crash_elf_data();
if (!cmem)
return -ENOMEM;
ret = walk_system_ram_res(0, -1, cmem,
prepare_elf64_ram_headers_callback);
ret = walk_system_ram_res(0, -1, cmem, prepare_elf64_ram_headers_callback);
if (ret)
goto out;
@ -265,24 +278,8 @@ static int prepare_elf_headers(struct kimage *image, void **addr,
goto out;
/* By default prepare 64bit headers */
ret = crash_prepare_elf64_headers(cmem,
IS_ENABLED(CONFIG_X86_64), addr, sz);
if (ret)
goto out;
ret = crash_prepare_elf64_headers(cmem, IS_ENABLED(CONFIG_X86_64), addr, sz);
/*
* If a range matches backup region, adjust offset to backup
* segment.
*/
ehdr = (Elf64_Ehdr *)*addr;
phdr = (Elf64_Phdr *)(ehdr + 1);
for (i = 0; i < ehdr->e_phnum; phdr++, i++)
if (phdr->p_type == PT_LOAD &&
phdr->p_paddr == image->arch.backup_src_start &&
phdr->p_memsz == image->arch.backup_src_sz) {
phdr->p_offset = image->arch.backup_load_addr;
break;
}
out:
vfree(cmem);
return ret;
@ -296,8 +293,7 @@ static int add_e820_entry(struct boot_params *params, struct e820_entry *entry)
if (nr_e820_entries >= E820_MAX_ENTRIES_ZEROPAGE)
return 1;
memcpy(&params->e820_table[nr_e820_entries], entry,
sizeof(struct e820_entry));
memcpy(&params->e820_table[nr_e820_entries], entry, sizeof(struct e820_entry));
params->e820_entries++;
return 0;
}
@ -321,19 +317,11 @@ static int memmap_exclude_ranges(struct kimage *image, struct crash_mem *cmem,
unsigned long long mend)
{
unsigned long start, end;
int ret = 0;
cmem->ranges[0].start = mstart;
cmem->ranges[0].end = mend;
cmem->nr_ranges = 1;
/* Exclude Backup region */
start = image->arch.backup_load_addr;
end = start + image->arch.backup_src_sz - 1;
ret = crash_exclude_mem_range(cmem, start, end);
if (ret)
return ret;
/* Exclude elf header region */
start = image->arch.elf_load_addr;
end = start + image->arch.elf_headers_sz - 1;
@ -356,28 +344,28 @@ int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params)
memset(&cmd, 0, sizeof(struct crash_memmap_data));
cmd.params = params;
/* Add first 640K segment */
ei.addr = image->arch.backup_src_start;
ei.size = image->arch.backup_src_sz;
ei.type = E820_TYPE_RAM;
add_e820_entry(params, &ei);
/* Add the low 1M */
cmd.type = E820_TYPE_RAM;
flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
walk_iomem_res_desc(IORES_DESC_NONE, flags, 0, (1<<20)-1, &cmd,
memmap_entry_callback);
/* Add ACPI tables */
cmd.type = E820_TYPE_ACPI;
flags = IORESOURCE_MEM | IORESOURCE_BUSY;
walk_iomem_res_desc(IORES_DESC_ACPI_TABLES, flags, 0, -1, &cmd,
memmap_entry_callback);
memmap_entry_callback);
/* Add ACPI Non-volatile Storage */
cmd.type = E820_TYPE_NVS;
walk_iomem_res_desc(IORES_DESC_ACPI_NV_STORAGE, flags, 0, -1, &cmd,
memmap_entry_callback);
memmap_entry_callback);
/* Add e820 reserved ranges */
cmd.type = E820_TYPE_RESERVED;
flags = IORESOURCE_MEM;
walk_iomem_res_desc(IORES_DESC_RESERVED, flags, 0, -1, &cmd,
memmap_entry_callback);
memmap_entry_callback);
/* Add crashk_low_res region */
if (crashk_low_res.end) {
@ -388,8 +376,7 @@ int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params)
}
/* Exclude some ranges from crashk_res and add rest to memmap */
ret = memmap_exclude_ranges(image, cmem, crashk_res.start,
crashk_res.end);
ret = memmap_exclude_ranges(image, cmem, crashk_res.start, crashk_res.end);
if (ret)
goto out;
@ -409,55 +396,12 @@ int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params)
return ret;
}
static int determine_backup_region(struct resource *res, void *arg)
{
struct kimage *image = arg;
image->arch.backup_src_start = res->start;
image->arch.backup_src_sz = resource_size(res);
/* Expecting only one range for backup region */
return 1;
}
int crash_load_segments(struct kimage *image)
{
int ret;
struct kexec_buf kbuf = { .image = image, .buf_min = 0,
.buf_max = ULONG_MAX, .top_down = false };
/*
* Determine and load a segment for backup area. First 640K RAM
* region is backup source
*/
ret = walk_system_ram_res(KEXEC_BACKUP_SRC_START, KEXEC_BACKUP_SRC_END,
image, determine_backup_region);
/* Zero or postive return values are ok */
if (ret < 0)
return ret;
/* Add backup segment. */
if (image->arch.backup_src_sz) {
kbuf.buffer = &crash_zero_bytes;
kbuf.bufsz = sizeof(crash_zero_bytes);
kbuf.memsz = image->arch.backup_src_sz;
kbuf.buf_align = PAGE_SIZE;
/*
* Ideally there is no source for backup segment. This is
* copied in purgatory after crash. Just add a zero filled
* segment for now to make sure checksum logic works fine.
*/
ret = kexec_add_buffer(&kbuf);
if (ret)
return ret;
image->arch.backup_load_addr = kbuf.mem;
pr_debug("Loaded backup region at 0x%lx backup_start=0x%lx memsz=0x%lx\n",
image->arch.backup_load_addr,
image->arch.backup_src_start, kbuf.memsz);
}
/* Prepare elf headers and add a segment */
ret = prepare_elf_headers(image, &kbuf.buffer, &kbuf.bufsz);
if (ret)

47
arch/x86/kernel/machine_kexec_64.c
View File

@ -298,48 +298,6 @@ static void load_segments(void)
);
}
#ifdef CONFIG_KEXEC_FILE
/* Update purgatory as needed after various image segments have been prepared */
static int arch_update_purgatory(struct kimage *image)
{
int ret = 0;
if (!image->file_mode)
return 0;
/* Setup copying of backup region */
if (image->type == KEXEC_TYPE_CRASH) {
ret = kexec_purgatory_get_set_symbol(image,
"purgatory_backup_dest",
&image->arch.backup_load_addr,
sizeof(image->arch.backup_load_addr), 0);
if (ret)
return ret;
ret = kexec_purgatory_get_set_symbol(image,
"purgatory_backup_src",
&image->arch.backup_src_start,
sizeof(image->arch.backup_src_start), 0);
if (ret)
return ret;
ret = kexec_purgatory_get_set_symbol(image,
"purgatory_backup_sz",
&image->arch.backup_src_sz,
sizeof(image->arch.backup_src_sz), 0);
if (ret)
return ret;
}
return ret;
}
#else /* !CONFIG_KEXEC_FILE */
static inline int arch_update_purgatory(struct kimage *image)
{
return 0;
}
#endif /* CONFIG_KEXEC_FILE */
int machine_kexec_prepare(struct kimage *image)
{
unsigned long start_pgtable;
@ -353,11 +311,6 @@ int machine_kexec_prepare(struct kimage *image)
if (result)
return result;
/* update purgatory as needed */
result = arch_update_purgatory(image);
if (result)
return result;
return 0;
}

19
arch/x86/purgatory/purgatory.c
View File

@ -14,28 +14,10 @@
#include "../boot/string.h"
unsigned long purgatory_backup_dest __section(.kexec-purgatory);
unsigned long purgatory_backup_src __section(.kexec-purgatory);
unsigned long purgatory_backup_sz __section(.kexec-purgatory);
u8 purgatory_sha256_digest[SHA256_DIGEST_SIZE] __section(.kexec-purgatory);
struct kexec_sha_region purgatory_sha_regions[KEXEC_SEGMENT_MAX] __section(.kexec-purgatory);
/*
* On x86, second kernel requries first 640K of memory to boot. Copy
* first 640K to a backup region in reserved memory range so that second
* kernel can use first 640K.
*/
static int copy_backup_region(void)
{
if (purgatory_backup_dest) {
memcpy((void *)purgatory_backup_dest,
(void *)purgatory_backup_src, purgatory_backup_sz);
}
return 0;
}
static int verify_sha256_digest(void)
{
struct kexec_sha_region *ptr, *end;
@ -66,7 +48,6 @@ void purgatory(void)
for (;;)
;
}
copy_backup_region();
}
/*

2
arch/x86/realmode/init.c
View File

@ -8,6 +8,7 @@
#include <asm/pgtable.h>
#include <asm/realmode.h>
#include <asm/tlbflush.h>
#include <asm/crash.h>
struct real_mode_header *real_mode_header;
u32 *trampoline_cr4_features;
@ -34,6 +35,7 @@ void __init reserve_real_mode(void)
memblock_reserve(mem, size);
set_real_mode_mem(mem);
crash_reserve_low_1M();
}
static void __init setup_real_mode(void)