From 7c321eb2b843bf25946100b7e2de4054f71ec068 Mon Sep 17 00:00:00 2001
From: Lianbo Jiang <lijiang@redhat.com>
Date: Fri, 8 Nov 2019 17:00:26 +0800
Subject: [PATCH] x86/kdump: Remove the backup region handling
MIME-Version: 1.0
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When the crashkernel kernel command line option is specified, the low
1M memory will always be reserved now. Therefore, it's not necessary to
create a backup region anymore and also no need to copy the contents of
the first 640k to it.
Remove all the code related to handling that backup region.
[ bp: Massage commit message. ]
Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: bhe@redhat.com
Cc: Dave Young <dyoung@redhat.com>
Cc: d.hatayama@fujitsu.com
Cc: dhowells@redhat.com
Cc: ebiederm@xmission.com
Cc: horms@verge.net.au
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jürgen Gross <jgross@suse.com>
Cc: kexec@lists.infradead.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: vgoyal@redhat.com
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20191108090027.11082-3-lijiang@redhat.com
---
arch/x86/include/asm/kexec.h | 10 ----
arch/x86/include/asm/purgatory.h | 10 ----
arch/x86/kernel/crash.c | 87 ++++--------------------------
arch/x86/kernel/machine_kexec_64.c | 47 ----------------
arch/x86/purgatory/purgatory.c | 19 -------
5 files changed, 11 insertions(+), 162 deletions(-)
diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index 5e7d6b46de97d..6802c59e82523 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -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;
diff --git a/arch/x86/include/asm/purgatory.h b/arch/x86/include/asm/purgatory.h
index 92c34e517da18..5528e93250494 100644
--- a/arch/x86/include/asm/purgatory.h
+++ b/arch/x86/include/asm/purgatory.h
@@ -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 */
diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index ff25a2ea271cf..a16ec92b70f5a 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -188,8 +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;
@@ -232,6 +230,11 @@ 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)
@@ -261,9 +264,7 @@ 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)
@@ -282,22 +283,7 @@ static int prepare_elf_headers(struct kimage *image, void **addr,
/* By default prepare 64bit headers */
ret = crash_prepare_elf64_headers(cmem,
IS_ENABLED(CONFIG_X86_64), addr, sz);
- if (ret)
- goto out;
- /*
- * 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;
@@ -336,19 +322,11 @@ 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;
@@ -371,11 +349,11 @@ 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;
@@ -424,55 +402,12 @@ out:
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)
diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index 5dcd438ad8f25..16e125a50b333 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -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;
}
diff --git a/arch/x86/purgatory/purgatory.c b/arch/x86/purgatory/purgatory.c
index 3b95410ff0f88..2961234d07952 100644
--- a/arch/x86/purgatory/purgatory.c
+++ b/arch/x86/purgatory/purgatory.c
@@ -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();
}
/*
--
2.30.2