From 40c03992bc470e29d0cc33e6f290916434092d76 Mon Sep 17 00:00:00 2001
From: Yuanhe Shu <xiangzao@linux.alibaba.com>
Date: Mon, 18 Sep 2023 19:48:50 +0800
Subject: [PATCH] Add pstore segment support

Add pstore segment thus it is able to record log of kdump process

Signed-off-by: Yuanhe Shu <xiangzao@linux.alibaba.com>
---
 kexec/arch/arm64/crashdump-arm64.c |  5 ++
 kexec/arch/i386/crashdump-x86.c    | 12 ++++-
 kexec/kexec.c                      | 80 ++++++++++++++++++++++++++++++
 kexec/kexec.h                      |  5 ++
 4 files changed, 100 insertions(+), 2 deletions(-)

diff --git a/kexec/arch/arm64/crashdump-arm64.c b/kexec/arch/arm64/crashdump-arm64.c
index 3098315..6aa954c 100644
--- a/kexec/arch/arm64/crashdump-arm64.c
+++ b/kexec/arch/arm64/crashdump-arm64.c
@@ -125,6 +125,11 @@ static int crash_get_memory_ranges(void)
 	if (!usablemem_rgns.size)
 		return -EINVAL;
 
+	usablemem_rgns.ranges[usablemem_rgns.size - 1].end -= PSTORE_SIZE;
+
+	dbgprintf("Created pstore segment at 0x%lx\n",
+			usablemem_rgns.ranges[usablemem_rgns.size - 1].end);
+
 	dbgprint_mem_range("Reserved memory range",
 			usablemem_rgns.ranges, usablemem_rgns.size);
 
diff --git a/kexec/arch/i386/crashdump-x86.c b/kexec/arch/i386/crashdump-x86.c
index df1f24c..3614007 100644
--- a/kexec/arch/i386/crashdump-x86.c
+++ b/kexec/arch/i386/crashdump-x86.c
@@ -823,7 +823,7 @@ int load_crashdump_segments(struct kexec_info *info, char* mod_cmdline,
 				unsigned long max_addr, unsigned long min_base)
 {
 	void *tmp;
-	unsigned long sz, bufsz, memsz, elfcorehdr;
+	unsigned long sz, bufsz, memsz, elfcorehdr, pstore_sz, pstore_start;
 	int nr_ranges = 0, nr_memmap = 0, align = 1024, i;
 	struct memory_range *mem_range, *memmap_p;
 	struct crash_elf_info elf_info;
@@ -923,6 +923,14 @@ int load_crashdump_segments(struct kexec_info *info, char* mod_cmdline,
 		}
 	}
 
+	pstore_sz = _ALIGN(PSTORE_SIZE, align);
+	pstore_start = (unsigned long)crash_reserved_mem[crash_reserved_mem_nr - 1].start;
+	dbgprintf("Created pstore segment at 0x%lx\n", pstore_start);
+	if (delete_memmap(memmap_p, &nr_memmap, pstore_start, pstore_sz) < 0) {
+		free(memmap_p);
+		return EFAILED;
+	}
+
 	/* Create elf header segment and store crash image data. */
 	if (arch_options.core_header_type == CORE_TYPE_ELF64) {
 		if (crash_create_elf64_headers(info, &elf_info, mem_range,
@@ -1004,7 +1012,7 @@ int get_crash_kernel_load_range(uint64_t *start, uint64_t *end)
 	if (!crash_reserved_mem_nr)
 		return -1;
 
-	*start = crash_reserved_mem[crash_reserved_mem_nr - 1].start;
+	*start = crash_reserved_mem[crash_reserved_mem_nr - 1].start + PSTORE_SIZE;
 	*end = crash_reserved_mem[crash_reserved_mem_nr - 1].end;
 
 	return 0;
diff --git a/kexec/kexec.c b/kexec/kexec.c
index 829a6ea..c1cb00e 100644
--- a/kexec/kexec.c
+++ b/kexec/kexec.c
@@ -40,6 +40,7 @@
 #endif
 #include <getopt.h>
 #include <ctype.h>
+#include <elf.h>
 
 #include "config.h"
 
@@ -638,6 +639,79 @@ char *slurp_decompress_file(const char *filename, off_t *r_size)
 	return kernel_buf;
 }
 
+static int readlog(unsigned long long paddrbase)
+{
+	const char kcore[] = "/proc/kcore";
+        Elf64_Ehdr *elf64;
+        Elf64_Phdr *load64, *notes64, *lp64;
+        char eheader[MAX_KCORE_ELF_HEADER_SIZE], console_buf[1000000], tty_buf[100000];
+        int fd, i, segments;
+        unsigned long long console_offset, tty_offset, console_vaddr, tty_vaddr,
+				console_paddr, tty_paddr, page_offset;
+        const unsigned long long pud_mask = ~((1 << 30) - 1);
+
+		#ifdef __x86_64__
+			page_offset = 0;
+		#endif
+		#ifdef __aarch64__
+			page_offset = 0xfffeffffc0000000;
+		#endif
+        console_paddr = paddrbase + 0xe00c;
+        tty_paddr = paddrbase + 0x5000c;
+
+        if ((fd = open(kcore, O_RDONLY)) < 0) {
+                fprintf(stderr, "Cannot open %s: %s\n", kcore, strerror(errno));
+                return -1;
+        }
+
+        if (read(fd, eheader, MAX_KCORE_ELF_HEADER_SIZE) != MAX_KCORE_ELF_HEADER_SIZE) {
+                fprintf(stderr, "Cannot read %s: %s\n", kcore, strerror(errno));
+                return -1;
+        }
+
+        elf64 = (Elf64_Ehdr *)&eheader[0];
+
+        notes64 = (Elf64_Phdr *)&eheader[elf64->e_phoff];
+        load64 = notes64 + 1;
+
+        segments = elf64->e_phnum - 1;
+
+        if (page_offset == 0) {
+            for ( i = 0; i < segments; i++) {
+                lp64 = load64 + i;
+                if (lp64->p_type == PT_LOAD)
+                    if ((page_offset == 0) | page_offset > (lp64->p_vaddr & pud_mask))
+                        page_offset = lp64->p_vaddr & pud_mask;
+            }
+        }
+        console_vaddr = console_paddr + page_offset;
+        tty_vaddr = tty_paddr + page_offset;
+
+        for ( i = 0; i < segments; i++) {
+                lp64 = load64 + i;
+                if ((console_vaddr >= lp64->p_vaddr) && (console_vaddr < (lp64->p_vaddr + lp64->p_memsz))) {
+                        console_offset = console_vaddr - lp64->p_vaddr + lp64->p_offset;
+                        tty_offset = tty_vaddr - lp64->p_vaddr + lp64->p_offset;
+                        break;
+                }
+        }
+
+        memset(console_buf, 0, sizeof(console_buf));
+        memset(tty_buf, 0, sizeof(tty_buf));
+
+        off_t c_offset = lseek(fd, console_offset, SEEK_SET);
+        size_t c_size = read(fd, console_buf, 1000000);
+
+        off_t t_offset = lseek(fd, tty_offset, SEEK_SET);
+        size_t t_size = read(fd, tty_buf, 100000);
+
+        printf("console log: \n%s\nttylog:\n%s\n", console_buf, tty_buf);
+
+        close(fd);
+
+        return 0;
+}
+
 static void update_purgatory(struct kexec_info *info)
 {
 	static const uint8_t null_buf[256];
@@ -1016,6 +1090,7 @@ void usage(void)
 	       "\n"
 	       " -h, --help           Print this help.\n"
 	       " -v, --version        Print the version of kexec.\n"
+	       " -r, --read           Print the logs of kdump process.\n"
 	       " -f, --force          Force an immediate kexec,\n"
 	       "                      don't call shutdown.\n"
 	       " -i, --no-checks      Fast reboot, no memory integrity checks.\n"
@@ -1417,6 +1492,7 @@ int main(int argc, char *argv[])
 	int opt;
 	int result = 0;
 	int fileind;
+	unsigned long long phy_addr;
 	static const struct option options[] = {
 		KEXEC_ALL_OPTIONS
 		{ 0, 0, 0, 0},
@@ -1439,6 +1515,10 @@ int main(int argc, char *argv[])
 		case OPT_VERSION:
 			version();
 			return 0;
+		case OPT_READ:
+			phy_addr = strtoul(optarg, &endptr, 0);
+			readlog(phy_addr);
+			return 0;
 		case OPT_DEBUG:
 			kexec_debug = 1;
 			break;
diff --git a/kexec/kexec.h b/kexec/kexec.h
index 8a05644..899f01b 100644
--- a/kexec/kexec.h
+++ b/kexec/kexec.h
@@ -232,9 +232,11 @@ extern int file_types;
 #define OPT_LOAD_LIVE_UPDATE	263
 #define OPT_EXEC_LIVE_UPDATE	264
 #define OPT_MAX			265
+#define OPT_READ		266
 #define KEXEC_OPTIONS \
 	{ "help",		0, 0, OPT_HELP }, \
 	{ "version",		0, 0, OPT_VERSION }, \
+	{ "read",		1, 0, OPT_READ }, \
 	{ "force",		0, 0, OPT_FORCE }, \
 	{ "no-checks",		0, 0, OPT_NOCHECKS }, \
 	{ "no-ifdown",		0, 0, OPT_NOIFDOWN }, \
@@ -318,6 +320,9 @@ const char * proc_iomem(void);
 
 #define MAX_LINE	160
 
+#define PSTORE_SIZE 0x60000
+#define MAX_KCORE_ELF_HEADER_SIZE (32768)
+
 char *concat_cmdline(const char *base, const char *append);
 void cmdline_add_liveupdate(char **base);
 
-- 
2.32.0 (Apple Git-132)