[PATCH] Partially revert "MIPS: Remove old core dump functions"

[minyard@acm.org]

From: Corey Minyard <cminyard@mvista.com>

This reverts part of commit 30852ad0039b4a54b5062efd66877125e519dc30,
which removed some ELF coredump functions from MIPS.  They are no
longer needed for normal coredumps, but they are still needed for
kdump.  The kernel crashes when doing a kdump shutdown because
elf_core_copy_kernel_regs() needs a MIPS-specific version and the
reverted commit removes it.

This change adds back in ELF_CORE_COPY_REGS() and the required
support for it.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
---
 arch/mips/include/asm/elf.h |  7 +++++++
 arch/mips/kernel/process.c  | 22 ++++++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/arch/mips/include/asm/elf.h b/arch/mips/include/asm/elf.h
index 2b3dc29..600db7b 100644
--- a/arch/mips/include/asm/elf.h
+++ b/arch/mips/include/asm/elf.h
@@ -414,6 +414,13 @@ do {									\
 
 #endif /* CONFIG_64BIT */
 
+struct pt_regs;
+
+extern void elf_dump_regs(elf_greg_t *, struct pt_regs *regs);
+
+#define ELF_CORE_COPY_REGS(elf_regs, regs)                     \
+       elf_dump_regs((elf_greg_t *)&(elf_regs), regs);
+
 #define CORE_DUMP_USE_REGSET
 #define ELF_EXEC_PAGESIZE	PAGE_SIZE
 
diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index fbbf5fc..0d63aa1 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -180,6 +180,28 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
 	return 0;
 }
 
+void elf_dump_regs(elf_greg_t *gp, struct pt_regs *regs)
+{
+	int i;
+
+	for (i = 0; i < EF_R0; i++)
+		gp[i] = 0;
+	gp[EF_R0] = 0;
+	for (i = 1; i <= 31; i++)
+		gp[EF_R0 + i] = regs->regs[i];
+	gp[EF_R26] = 0;
+	gp[EF_R27] = 0;
+	gp[EF_LO] = regs->lo;
+	gp[EF_HI] = regs->hi;
+	gp[EF_CP0_EPC] = regs->cp0_epc;
+	gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr;
+	gp[EF_CP0_STATUS] = regs->cp0_status;
+	gp[EF_CP0_CAUSE] = regs->cp0_cause;
+#ifdef EF_UNUSED0
+	gp[EF_UNUSED0] = 0;
+#endif
+}
+
 #ifdef CONFIG_CC_STACKPROTECTOR
 #include <linux/stackprotector.h>
 unsigned long __stack_chk_guard __read_mostly;
-- 
2.7.4