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Date: Sun, 11 Apr 2010 23:04:17 -0700
From: David VomLehn <dvomlehn@...co.com>
To: to@...mlehn-lnx2.corp.sa.net,
"linux_arch"@dvomlehn-lnx2.corp.sa.net,
linux_arch@...mlehn-lnx2.corp.sa.net
Cc: akpm@...ux-foundation.org, linux-kernel@...r.kernel.org,
maint_arch@...mlehn-lnx2.corp.sa.net
Subject: [PATCH 13/23] Make register values available to MIPS panic
notifiers
The save_ptregs() function has been verified to work.
Signed-off-by: David VomLehn <dvomlehn@...co.com>
---
arch/mips/include/asm/ptrace.h | 134 ++++++++++++++++++++++++++++++++++++++++
1 files changed, 134 insertions(+), 0 deletions(-)
diff --git a/arch/mips/include/asm/ptrace.h b/arch/mips/include/asm/ptrace.h
index ce47118..2b75856 100644
--- a/arch/mips/include/asm/ptrace.h
+++ b/arch/mips/include/asm/ptrace.h
@@ -114,10 +114,13 @@ struct pt_watch_regs {
#ifdef __KERNEL__
+#include <linux/kernel.h>
#include <linux/compiler.h>
#include <linux/linkage.h>
#include <linux/types.h>
#include <asm/isadep.h>
+#include <asm/mipsregs.h>
+#include <asm/asm.h>
struct task_struct;
@@ -139,6 +142,7 @@ extern int ptrace_set_watch_regs(struct task_struct *child,
#define instruction_pointer(regs) ((regs)->cp0_epc)
#define profile_pc(regs) instruction_pointer(regs)
+extern void show_regs(struct pt_regs *regs);
extern asmlinkage void do_syscall_trace(struct pt_regs *regs, int entryexit);
@@ -150,6 +154,136 @@ static inline void die_if_kernel(const char *str, const struct pt_regs *regs)
die(str, regs);
}
+#include <linux/ptreg.h>
+
+#define PTREG_SAVE(r, name) STR(LONG_S) " " #r ", %[" #name "]\n"
+#define PTREG_SAVE_GPR(i) _PTREG_SAVE_IDX($, gpr, i)
+
+#define PTREG_OUT_GPR(regsp, i) _PTREG_OUT_IDX(regsp, regs, gpr, i)
+
+#define arch_has_save_ptregs 1
+
+/**
+ * save_ptregs - save processor registers for backtracing
+ * @regs: Pointer to &struct pt_regs structure in which to save the
+ * registers
+ *
+ * Returns a constant pointer to @regs.
+ *
+ * This saves all the GPRs and the EPC, Cause, and Status values for
+ * coprocessor 0.
+ *
+ * This function must be called first in a function. There must be no
+ * auto variables defined that are initialized before calling this function.
+ */
+static __always_inline
+const struct pt_regs *save_ptregs(register struct pt_regs *regs)
+{
+ /* The compiler restricts us to 30 operands in an asm construct, so we
+ * have to break the register saving into two pieces. We can skip
+ * saving the zero register in the first piece, since its value is
+ * constant. Since we can ensure no calls are made between the two
+ * pieces, we can also delay saving the ra register to the second
+ * piece. */
+ __asm__ __volatile__ (
+ " .set noat\n"
+ PTREG_SAVE_GPR(1)
+ " .set at\n"
+ PTREG_SAVE_GPR(2)
+ PTREG_SAVE_GPR(3)
+ PTREG_SAVE_GPR(4)
+ PTREG_SAVE_GPR(5)
+ PTREG_SAVE_GPR(6)
+ PTREG_SAVE_GPR(7)
+ PTREG_SAVE_GPR(8)
+ PTREG_SAVE_GPR(9)
+ PTREG_SAVE_GPR(10)
+ PTREG_SAVE_GPR(11)
+ PTREG_SAVE_GPR(12)
+ PTREG_SAVE_GPR(13)
+ PTREG_SAVE_GPR(14)
+ PTREG_SAVE_GPR(15)
+ PTREG_SAVE_GPR(16)
+ PTREG_SAVE_GPR(17)
+ PTREG_SAVE_GPR(18)
+ PTREG_SAVE_GPR(19)
+ PTREG_SAVE_GPR(20)
+ PTREG_SAVE_GPR(21)
+ PTREG_SAVE_GPR(22)
+ PTREG_SAVE_GPR(23)
+ PTREG_SAVE_GPR(24)
+ PTREG_SAVE_GPR(25)
+ PTREG_SAVE_GPR(26)
+ PTREG_SAVE_GPR(27)
+ PTREG_SAVE_GPR(28)
+ PTREG_SAVE_GPR(29)
+ PTREG_SAVE_GPR(30)
+ :
+ PTREG_OUT_GPR(regs, 1),
+ PTREG_OUT_GPR(regs, 2),
+ PTREG_OUT_GPR(regs, 3),
+ PTREG_OUT_GPR(regs, 4),
+ PTREG_OUT_GPR(regs, 5),
+ PTREG_OUT_GPR(regs, 6),
+ PTREG_OUT_GPR(regs, 7),
+ PTREG_OUT_GPR(regs, 8),
+ PTREG_OUT_GPR(regs, 9),
+ PTREG_OUT_GPR(regs, 10),
+ PTREG_OUT_GPR(regs, 11),
+ PTREG_OUT_GPR(regs, 12),
+ PTREG_OUT_GPR(regs, 13),
+ PTREG_OUT_GPR(regs, 14),
+ PTREG_OUT_GPR(regs, 15),
+ PTREG_OUT_GPR(regs, 16),
+ PTREG_OUT_GPR(regs, 17),
+ PTREG_OUT_GPR(regs, 18),
+ PTREG_OUT_GPR(regs, 19),
+ PTREG_OUT_GPR(regs, 20),
+ PTREG_OUT_GPR(regs, 21),
+ PTREG_OUT_GPR(regs, 22),
+ PTREG_OUT_GPR(regs, 23),
+ PTREG_OUT_GPR(regs, 24),
+ PTREG_OUT_GPR(regs, 25),
+ PTREG_OUT_GPR(regs, 26),
+ PTREG_OUT_GPR(regs, 27),
+ PTREG_OUT_GPR(regs, 28),
+ PTREG_OUT_GPR(regs, 29),
+ PTREG_OUT_GPR(regs, 30)
+ :
+ :
+ "$1"
+ );
+
+ /* This is the second part, where we save the ra register. We then
+ * set the EPC register to the location immediately after the save
+ * of the ra register since that's the point at which the saved GPRs
+ * correspond with the actual GPRs. */
+ __asm__ __volatile__ (
+ PTREG_SAVE_GPR(31)
+ "1:\n"
+ " .set noat\n"
+ STR(PTR_LA) " $at, 1b\n"
+ PTREG_SAVE($at, cp0_epc)
+ " .set at\n"
+ :
+ PTREG_OUT_GPR(regs, 31),
+ PTREG_OUT(regs, cp0_epc, cp0_epc)
+ :
+ :
+ "$1"
+ );
+
+ /* The zero register is always, well, zero. */
+ regs->regs[0] = 0;
+
+ /* Grab the values of the coprocessor zero Status and Cause registers.
+ * We haven't done anything that will affect them up to this point,
+ * so waiting until here to save them is a reasonable thing to do. */
+ regs->cp0_status = read_c0_status();
+ regs->cp0_cause = read_c0_cause();
+
+ return regs;
+}
#endif
#endif /* _ASM_PTRACE_H */
--
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