Commit 6312e0ee authored by Atsushi Nemoto's avatar Atsushi Nemoto Committed by Ralf Baechle

[MIPS] Add some debugfs files to debug unaligned accesses

Currently a number of unaligned instructions is counted but not used.
Add /debug/mips/unaligned_instructions file to show the value.

And add /debug/mips/unaligned_action to control behavior upon an
unaligned access.  Possible actions are:

0: silently fixup the unaligned access.
1: send SIGBUS.
2: dump registers, process name, etc. and fixup.
Signed-off-by: default avatarAtsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent 2db30150
......@@ -20,6 +20,7 @@
#include <linux/highmem.h>
#include <linux/console.h>
#include <linux/pfn.h>
#include <linux/debugfs.h>
#include <asm/addrspace.h>
#include <asm/bootinfo.h>
......@@ -574,3 +575,18 @@ __setup("nodsp", dsp_disable);
unsigned long kernelsp[NR_CPUS];
unsigned long fw_arg0, fw_arg1, fw_arg2, fw_arg3;
#ifdef CONFIG_DEBUG_FS
struct dentry *mips_debugfs_dir;
static int __init debugfs_mips(void)
{
struct dentry *d;
d = debugfs_create_dir("mips", NULL);
if (IS_ERR(d))
return PTR_ERR(d);
mips_debugfs_dir = d;
return 0;
}
arch_initcall(debugfs_mips);
#endif
......@@ -77,6 +77,7 @@
#include <linux/signal.h>
#include <linux/smp.h>
#include <linux/sched.h>
#include <linux/debugfs.h>
#include <asm/asm.h>
#include <asm/branch.h>
#include <asm/byteorder.h>
......@@ -87,9 +88,18 @@
#define STR(x) __STR(x)
#define __STR(x) #x
#ifdef CONFIG_PROC_FS
unsigned long unaligned_instructions;
enum {
UNALIGNED_ACTION_QUIET,
UNALIGNED_ACTION_SIGNAL,
UNALIGNED_ACTION_SHOW,
};
#ifdef CONFIG_DEBUG_FS
static u32 unaligned_instructions;
static u32 unaligned_action;
#else
#define unaligned_action UNALIGNED_ACTION_QUIET
#endif
extern void show_registers(struct pt_regs *regs);
static inline int emulate_load_store_insn(struct pt_regs *regs,
void __user *addr, unsigned int __user *pc,
......@@ -459,7 +469,7 @@ static inline int emulate_load_store_insn(struct pt_regs *regs,
goto sigill;
}
#ifdef CONFIG_PROC_FS
#ifdef CONFIG_DEBUG_FS
unaligned_instructions++;
#endif
......@@ -516,6 +526,10 @@ asmlinkage void do_ade(struct pt_regs *regs)
pc = (unsigned int __user *) exception_epc(regs);
if (user_mode(regs) && (current->thread.mflags & MF_FIXADE) == 0)
goto sigbus;
if (unaligned_action == UNALIGNED_ACTION_SIGNAL)
goto sigbus;
else if (unaligned_action == UNALIGNED_ACTION_SHOW)
show_registers(regs);
/*
* Do branch emulation only if we didn't forward the exception.
......@@ -546,3 +560,24 @@ sigbus:
* XXX On return from the signal handler we should advance the epc
*/
}
#ifdef CONFIG_DEBUG_FS
extern struct dentry *mips_debugfs_dir;
static int __init debugfs_unaligned(void)
{
struct dentry *d;
if (!mips_debugfs_dir)
return -ENODEV;
d = debugfs_create_u32("unaligned_instructions", S_IRUGO,
mips_debugfs_dir, &unaligned_instructions);
if (IS_ERR(d))
return PTR_ERR(d);
d = debugfs_create_u32("unaligned_action", S_IRUGO | S_IWUSR,
mips_debugfs_dir, &unaligned_action);
if (IS_ERR(d))
return PTR_ERR(d);
return 0;
}
__initcall(debugfs_unaligned);
#endif
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