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Diffstat (limited to 'arch/ia64/kernel/unaligned.c')
-rw-r--r--arch/ia64/kernel/unaligned.c89
1 files changed, 55 insertions, 34 deletions
diff --git a/arch/ia64/kernel/unaligned.c b/arch/ia64/kernel/unaligned.c
index 43b45b65ee5..622772b7fb6 100644
--- a/arch/ia64/kernel/unaligned.c
+++ b/arch/ia64/kernel/unaligned.c
@@ -13,10 +13,11 @@
* 2001/08/13 Correct size of extended floats (float_fsz) from 16 to 10 bytes.
* 2001/01/17 Add support emulation of unaligned kernel accesses.
*/
+#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/sched.h>
-#include <linux/smp_lock.h>
#include <linux/tty.h>
+#include <linux/ratelimit.h>
#include <asm/intrinsics.h>
#include <asm/processor.h>
@@ -24,12 +25,12 @@
#include <asm/uaccess.h>
#include <asm/unaligned.h>
-extern void die_if_kernel(char *str, struct pt_regs *regs, long err) __attribute__ ((noreturn));
+extern int die_if_kernel(char *str, struct pt_regs *regs, long err);
#undef DEBUG_UNALIGNED_TRAP
#ifdef DEBUG_UNALIGNED_TRAP
-# define DPRINT(a...) do { printk("%s %u: ", __FUNCTION__, __LINE__); printk (a); } while (0)
+# define DPRINT(a...) do { printk("%s %u: ", __func__, __LINE__); printk (a); } while (0)
# define DDUMP(str,vp,len) dump(str, vp, len)
static void
@@ -53,6 +54,15 @@ dump (const char *str, void *vp, size_t len)
#define SIGN_EXT9 0xffffffffffffff00ul
/*
+ * sysctl settable hook which tells the kernel whether to honor the
+ * IA64_THREAD_UAC_NOPRINT prctl. Because this is user settable, we want
+ * to allow the super user to enable/disable this for security reasons
+ * (i.e. don't allow attacker to fill up logs with unaligned accesses).
+ */
+int no_unaligned_warning;
+int unaligned_dump_stack;
+
+/*
* For M-unit:
*
* opcode | m | x6 |
@@ -666,9 +676,10 @@ emulate_load_updates (update_t type, load_store_t ld, struct pt_regs *regs, unsi
* just in case.
*/
if (ld.x6_op == 1 || ld.x6_op == 3) {
- printk(KERN_ERR "%s: register update on speculative load, error\n", __FUNCTION__);
- die_if_kernel("unaligned reference on speculative load with register update\n",
- regs, 30);
+ printk(KERN_ERR "%s: register update on speculative load, error\n", __func__);
+ if (die_if_kernel("unaligned reference on speculative load with register update\n",
+ regs, 30))
+ return;
}
@@ -1095,7 +1106,7 @@ emulate_load_floatpair (unsigned long ifa, load_store_t ld, struct pt_regs *regs
*/
if (ld.x6_op == 1 || ld.x6_op == 3)
printk(KERN_ERR "%s: register update on speculative load pair, error\n",
- __FUNCTION__);
+ __func__);
setreg(ld.r3, ifa, 0, regs);
}
@@ -1273,23 +1284,9 @@ emulate_store_float (unsigned long ifa, load_store_t ld, struct pt_regs *regs)
/*
* Make sure we log the unaligned access, so that user/sysadmin can notice it and
* eventually fix the program. However, we don't want to do that for every access so we
- * pace it with jiffies. This isn't really MP-safe, but it doesn't really have to be
- * either...
+ * pace it with jiffies.
*/
-static int
-within_logging_rate_limit (void)
-{
- static unsigned long count, last_time;
-
- if (jiffies - last_time > 5*HZ)
- count = 0;
- if (++count < 5) {
- last_time = jiffies;
- return 1;
- }
- return 0;
-
-}
+static DEFINE_RATELIMIT_STATE(logging_rate_limit, 5 * HZ, 5);
void
ia64_handle_unaligned (unsigned long ifa, struct pt_regs *regs)
@@ -1308,7 +1305,8 @@ ia64_handle_unaligned (unsigned long ifa, struct pt_regs *regs)
if (ia64_psr(regs)->be) {
/* we don't support big-endian accesses */
- die_if_kernel("big-endian unaligned accesses are not supported", regs, 0);
+ if (die_if_kernel("big-endian unaligned accesses are not supported", regs, 0))
+ return;
goto force_sigbus;
}
@@ -1323,14 +1321,16 @@ ia64_handle_unaligned (unsigned long ifa, struct pt_regs *regs)
if ((current->thread.flags & IA64_THREAD_UAC_SIGBUS) != 0)
goto force_sigbus;
- if (!(current->thread.flags & IA64_THREAD_UAC_NOPRINT)
- && within_logging_rate_limit())
+ if (!no_unaligned_warning &&
+ !(current->thread.flags & IA64_THREAD_UAC_NOPRINT) &&
+ __ratelimit(&logging_rate_limit))
{
char buf[200]; /* comm[] is at most 16 bytes... */
size_t len;
len = sprintf(buf, "%s(%d): unaligned access to 0x%016lx, "
- "ip=0x%016lx\n\r", current->comm, current->pid,
+ "ip=0x%016lx\n\r", current->comm,
+ task_pid_nr(current),
ifa, regs->cr_iip + ipsr->ri);
/*
* Don't call tty_write_message() if we're in the kernel; we might
@@ -1339,12 +1339,29 @@ ia64_handle_unaligned (unsigned long ifa, struct pt_regs *regs)
if (user_mode(regs))
tty_write_message(current->signal->tty, buf);
buf[len-1] = '\0'; /* drop '\r' */
- printk(KERN_WARNING "%s", buf); /* watch for command names containing %s */
+ /* watch for command names containing %s */
+ printk(KERN_WARNING "%s", buf);
+ } else {
+ if (no_unaligned_warning) {
+ printk_once(KERN_WARNING "%s(%d) encountered an "
+ "unaligned exception which required\n"
+ "kernel assistance, which degrades "
+ "the performance of the application.\n"
+ "Unaligned exception warnings have "
+ "been disabled by the system "
+ "administrator\n"
+ "echo 0 > /proc/sys/kernel/ignore-"
+ "unaligned-usertrap to re-enable\n",
+ current->comm, task_pid_nr(current));
+ }
}
} else {
- if (within_logging_rate_limit())
+ if (__ratelimit(&logging_rate_limit)) {
printk(KERN_WARNING "kernel unaligned access to 0x%016lx, ip=0x%016lx\n",
ifa, regs->cr_iip + ipsr->ri);
+ if (unaligned_dump_stack)
+ dump_stack();
+ }
set_fs(KERNEL_DS);
}
@@ -1462,16 +1479,19 @@ ia64_handle_unaligned (unsigned long ifa, struct pt_regs *regs)
case LDFA_OP:
case LDFCCLR_OP:
case LDFCNC_OP:
- case LDF_IMM_OP:
- case LDFA_IMM_OP:
- case LDFCCLR_IMM_OP:
- case LDFCNC_IMM_OP:
if (u.insn.x)
ret = emulate_load_floatpair(ifa, u.insn, regs);
else
ret = emulate_load_float(ifa, u.insn, regs);
break;
+ case LDF_IMM_OP:
+ case LDFA_IMM_OP:
+ case LDFCCLR_IMM_OP:
+ case LDFCNC_IMM_OP:
+ ret = emulate_load_float(ifa, u.insn, regs);
+ break;
+
case STF_OP:
case STF_IMM_OP:
ret = emulate_store_float(ifa, u.insn, regs);
@@ -1505,7 +1525,8 @@ ia64_handle_unaligned (unsigned long ifa, struct pt_regs *regs)
ia64_handle_exception(regs, eh);
goto done;
}
- die_if_kernel("error during unaligned kernel access\n", regs, ret);
+ if (die_if_kernel("error during unaligned kernel access\n", regs, ret))
+ return;
/* NOT_REACHED */
}
force_sigbus:
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-12-05 23:09:14 +0000