Implement /dev/oldmem and /proc/vmcore support for ppc32.
It is used to provide crash dumps of the previously running kernel.
Signed-off-by: Dale Farnsworth <[EMAIL PROTECTED]>
---
arch/powerpc/kernel/crash_dump.c | 67 ++++++++++++++++++++++++++++++++++++++
include/asm-powerpc/kexec.h | 62 +++++++++++++++++++++++++++++++++--
2 files changed, 126 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/kernel/crash_dump.c b/arch/powerpc/kernel/crash_dump.c
index 77c0376..39a3d92 100644
--- a/arch/powerpc/kernel/crash_dump.c
+++ b/arch/powerpc/kernel/crash_dump.c
@@ -13,6 +13,7 @@
#include <linux/crash_dump.h>
#include <linux/bootmem.h>
+#include <linux/highmem.h>
#include <asm/kdump.h>
#include <asm/lmb.h>
#include <asm/firmware.h>
@@ -83,6 +84,7 @@ static int __init parse_savemaxmem(char *p)
}
__setup("savemaxmem=", parse_savemaxmem);
+#ifdef CONFIG_PPC64
/**
* copy_oldmem_page - copy one page from "oldmem"
* @pfn: page frame number to be copied
@@ -117,3 +119,68 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
iounmap(vaddr);
return csize;
}
+
+#else /* CONFIG_PPC64 */
+
+static void *kdump_buf_page;
+
+/**
+ * copy_oldmem_page - copy one page from "oldmem"
+ * @pfn: page frame number to be copied
+ * @buf: target memory address for the copy; this can be in kernel address
+ * space or user address space (see @userbuf)
+ * @csize: number of bytes to copy
+ * @offset: offset in bytes into the page (based on pfn) to begin the copy
+ * @userbuf: if set, @buf is in user address space, use copy_to_user(),
+ * otherwise @buf is in kernel address space, use memcpy().
+ *
+ * Copy a page from "oldmem". For this page, there is no pte mapped
+ * in the current kernel.
+ *
+ * Calling copy_to_user() in atomic context is not desirable. Hence first
+ * copying the data to a pre-allocated kernel page and then copying to user
+ * space in non-atomic context.
+ */
+ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
+ size_t csize, unsigned long offset, int userbuf)
+{
+ void *vaddr;
+
+ if (!csize)
+ return 0;
+
+ vaddr = kmap_atomic_pfn(pfn, KM_PTE0);
+
+ if (!userbuf) {
+ memcpy(buf, (vaddr + offset), csize);
+ kunmap_atomic(vaddr, KM_PTE0);
+ } else {
+ if (!kdump_buf_page) {
+ printk(KERN_WARNING "Kdump: Kdump buffer page not"
+ " allocated\n");
+ return -EFAULT;
+ }
+ copy_page(kdump_buf_page, vaddr);
+ kunmap_atomic(vaddr, KM_PTE0);
+ if (copy_to_user(buf, (kdump_buf_page + offset), csize))
+ return -EFAULT;
+ }
+
+ return csize;
+}
+
+static int __init kdump_buf_page_init(void)
+{
+ int ret = 0;
+
+ kdump_buf_page = kmalloc(PAGE_SIZE, GFP_KERNEL);
+ if (!kdump_buf_page) {
+ printk(KERN_WARNING "Kdump: Failed to allocate kdump buffer"
+ " page\n");
+ ret = -ENOMEM;
+ }
+
+ return ret;
+}
+arch_initcall(kdump_buf_page_init);
+#endif /* CONFIG_PPC64 */
diff --git a/include/asm-powerpc/kexec.h b/include/asm-powerpc/kexec.h
index b6f817b..8c213c0 100644
--- a/include/asm-powerpc/kexec.h
+++ b/include/asm-powerpc/kexec.h
@@ -101,11 +101,67 @@ static inline void crash_setup_regs(struct pt_regs
*newregs,
}
#else
/*
- * Provide a dummy definition to avoid build failures. Will remain
- * empty till crash dump support is enabled.
+ * This function is responsible for capturing register states if coming
+ * via panic or invoking dump using sysrq-trigger.
*/
static inline void crash_setup_regs(struct pt_regs *newregs,
- struct pt_regs *oldregs) { }
+ struct pt_regs *oldregs)
+{
+ if (oldregs)
+ memcpy(newregs, oldregs, sizeof(*newregs));
+ else {
+ /* FIXME Merge this with xmon_save_regs ?? */
+ unsigned long tmp1, tmp2;
+ __asm__ __volatile__ (
+ "stw 0,0(%2)\n"
+ "stw 1,4(%2)\n"
+ "stw 2,8(%2)\n"
+ "stw 3,12(%2)\n"
+ "stw 4,16(%2)\n"
+ "stw 5,20(%2)\n"
+ "stw 6,24(%2)\n"
+ "stw 7,28(%2)\n"
+ "stw 8,32(%2)\n"
+ "stw 9,36(%2)\n"
+ "stw 10,40(%2)\n"
+ "stw 11,44(%2)\n"
+ "stw 12,48(%2)\n"
+ "stw 13,52(%2)\n"
+ "stw 14,56(%2)\n"
+ "stw 15,60(%2)\n"
+ "stw 16,64(%2)\n"
+ "stw 17,68(%2)\n"
+ "stw 18,72(%2)\n"
+ "stw 19,76(%2)\n"
+ "stw 20,80(%2)\n"
+ "stw 21,84(%2)\n"
+ "stw 22,88(%2)\n"
+ "stw 23,92(%2)\n"
+ "stw 24,96(%2)\n"
+ "stw 25,100(%2)\n"
+ "stw 26,104(%2)\n"
+ "stw 27,108(%2)\n"
+ "stw 28,112(%2)\n"
+ "stw 29,116(%2)\n"
+ "stw 30,120(%2)\n"
+ "stw 31,124(%2)\n"
+ "mfmsr %0\n"
+ "stw %0,132(%2)\n"
+ "mfctr %0\n"
+ "stw %0,140(%2)\n"
+ "mflr %0\n"
+ "stw %0,144(%2)\n"
+ "bl 1f\n"
+ "1: mflr %1\n"
+ "stw %1,128(%2)\n"
+ "mtlr %0\n"
+ "mfxer %0\n"
+ "stw %0,148(%2)\n"
+ : "=&r" (tmp1), "=&r" (tmp2)
+ : "b" (newregs)
+ : "memory");
+ }
+}
#endif /* !__powerpc64 __ */
extern void kexec_smp_wait(void); /* get and clear naca physid, wait for
--
1.5.3.4
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