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authorLinus Torvalds <torvalds@linux-foundation.org>2008-09-08 15:55:18 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-09-08 15:55:18 -0700
commit82a28c794f27aac17d7a3ebd7f14d731a11a5532 (patch)
tree363be899124b4f8af5a54d7862be1b56be5f9adf
parentc1bad36054828b6a625afea39deb83d0e66e4336 (diff)
parent84c4f2f21a8e6e6d4bdfff95bf5ddc7925df4e01 (diff)
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/hskinnemoen/avr32-2.6
* 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/hskinnemoen/avr32-2.6: avr32: pm_standby low-power ram bug fix avr32: Fix lockup after Java stack underflow in user mode
-rw-r--r--arch/avr32/kernel/asm-offsets.c6
-rw-r--r--arch/avr32/kernel/entry-avr32b.S59
-rw-r--r--arch/avr32/mach-at32ap/pm-at32ap700x.S2
3 files changed, 64 insertions, 3 deletions
diff --git a/arch/avr32/kernel/asm-offsets.c b/arch/avr32/kernel/asm-offsets.c
index e4796c67a831..d6a8193a1d2f 100644
--- a/arch/avr32/kernel/asm-offsets.c
+++ b/arch/avr32/kernel/asm-offsets.c
@@ -4,6 +4,8 @@
* to extract and format the required data.
*/
+#include <linux/mm.h>
+#include <linux/sched.h>
#include <linux/thread_info.h>
#include <linux/kbuild.h>
@@ -17,4 +19,8 @@ void foo(void)
OFFSET(TI_rar_saved, thread_info, rar_saved);
OFFSET(TI_rsr_saved, thread_info, rsr_saved);
OFFSET(TI_restart_block, thread_info, restart_block);
+ BLANK();
+ OFFSET(TSK_active_mm, task_struct, active_mm);
+ BLANK();
+ OFFSET(MM_pgd, mm_struct, pgd);
}
diff --git a/arch/avr32/kernel/entry-avr32b.S b/arch/avr32/kernel/entry-avr32b.S
index 2b398cae110c..33d49377b8be 100644
--- a/arch/avr32/kernel/entry-avr32b.S
+++ b/arch/avr32/kernel/entry-avr32b.S
@@ -334,9 +334,64 @@ save_full_context_ex:
/* Low-level exception handlers */
handle_critical:
+ /*
+ * AT32AP700x errata:
+ *
+ * After a Java stack overflow or underflow trap, any CPU
+ * memory access may cause erratic behavior. This will happen
+ * when the four least significant bits of the JOSP system
+ * register contains any value between 9 and 15 (inclusive).
+ *
+ * Possible workarounds:
+ * - Don't use the Java Extension Module
+ * - Ensure that the stack overflow and underflow trap
+ * handlers do not do any memory access or trigger any
+ * exceptions before the overflow/underflow condition is
+ * cleared (by incrementing or decrementing the JOSP)
+ * - Make sure that JOSP does not contain any problematic
+ * value before doing any exception or interrupt
+ * processing.
+ * - Set up a critical exception handler which writes a
+ * known-to-be-safe value, e.g. 4, to JOSP before doing
+ * any further processing.
+ *
+ * We'll use the last workaround for now since we cannot
+ * guarantee that user space processes don't use Java mode.
+ * Non-well-behaving userland will be terminated with extreme
+ * prejudice.
+ */
+#ifdef CONFIG_CPU_AT32AP700X
+ /*
+ * There's a chance we can't touch memory, so temporarily
+ * borrow PTBR to save the stack pointer while we fix things
+ * up...
+ */
+ mtsr SYSREG_PTBR, sp
+ mov sp, 4
+ mtsr SYSREG_JOSP, sp
+ mfsr sp, SYSREG_PTBR
+ sub pc, -2
+
+ /* Push most of pt_regs on stack. We'll do the rest later */
sub sp, 4
- stmts --sp, r0-lr
- rcall save_full_context_ex
+ pushm r0-r12
+
+ /* PTBR mirrors current_thread_info()->task->active_mm->pgd */
+ get_thread_info r0
+ ld.w r1, r0[TI_task]
+ ld.w r2, r1[TSK_active_mm]
+ ld.w r3, r2[MM_pgd]
+ mtsr SYSREG_PTBR, r3
+#else
+ sub sp, 4
+ pushm r0-r12
+#endif
+ sub r0, sp, -(14 * 4)
+ mov r1, lr
+ mfsr r2, SYSREG_RAR_EX
+ mfsr r3, SYSREG_RSR_EX
+ pushm r0-r3
+
mfsr r12, SYSREG_ECR
mov r11, sp
rcall do_critical_exception
diff --git a/arch/avr32/mach-at32ap/pm-at32ap700x.S b/arch/avr32/mach-at32ap/pm-at32ap700x.S
index 5be4de65b209..17503b0ed6c9 100644
--- a/arch/avr32/mach-at32ap/pm-at32ap700x.S
+++ b/arch/avr32/mach-at32ap/pm-at32ap700x.S
@@ -134,7 +134,7 @@ pm_standby:
mov r11, SDRAMC_LPR_LPCB_SELF_RFR
bfins r10, r11, 0, 2 /* LPCB <- self Refresh */
sync 0 /* flush write buffer */
- st.w r12[SDRAMC_LPR], r11 /* put SDRAM in self-refresh mode */
+ st.w r12[SDRAMC_LPR], r10 /* put SDRAM in self-refresh mode */
ld.w r11, r12[SDRAMC_LPR]
unmask_interrupts
sleep CPU_SLEEP_FROZEN

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