| Message ID | 1369259730-25693-1-git-send-email-kamal@canonical.com |
|---|---|
| State | New |
| Headers | show |
diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c index 0c3ba9f..f4726dc 100644 --- a/arch/arm64/kernel/debug-monitors.c +++ b/arch/arm64/kernel/debug-monitors.c @@ -136,8 +136,6 @@ void disable_debug_monitors(enum debug_el el) */ static void clear_os_lock(void *unused) { - asm volatile("msr mdscr_el1, %0" : : "r" (0)); - isb(); asm volatile("msr oslar_el1, %0" : : "r" (0)); isb(); } diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S index f1d8b9b..a82ae88 100644 --- a/arch/arm64/mm/proc.S +++ b/arch/arm64/mm/proc.S @@ -119,8 +119,7 @@ ENTRY(__cpu_setup) mov x0, #3 << 20 msr cpacr_el1, x0 // Enable FP/ASIMD - mov x0, #1 - msr oslar_el1, x0 // Set the debug OS lock + msr mdscr_el1, xzr // Reset mdscr_el1 tlbi vmalle1is // invalidate I + D TLBs /* * Memory region attributes for LPAE:
This is a note to let you know that I have just added a patch titled arm64: debug: clear mdscr_el1 instead of taking the OS lock to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.8.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From aed0d169a09ab2b83e9dcc1ce91c2f94799fe0bf Mon Sep 17 00:00:00 2001 From: Will Deacon <will.deacon@arm.com> Date: Wed, 8 May 2013 17:01:12 +0100 Subject: arm64: debug: clear mdscr_el1 instead of taking the OS lock commit 9c413e25d95fd3c0abe23eadad66191b22baa549 upstream. During boot, we take the debug OS lock before interrupts are enabled. This is required to prevent clearing of PSTATE.D on the interrupt entry path, which could result in spurious debug exceptions before we've got round to resetting things like the hardware breakpoints registers to a sane state. A problem with this approach is that taking the OS lock prevents an external JTAG debugger from debugging the system, which is especially irritating during boot, where JTAG debugging can be most useful. This patch clears mdscr_el1 rather than taking the lock, clearing the MDE and KDE bits and preventing self-hosted hardware debug exceptions from occurring. Tested-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- arch/arm64/kernel/debug-monitors.c | 2 -- arch/arm64/mm/proc.S | 3 +-- 2 files changed, 1 insertion(+), 4 deletions(-) -- 1.8.1.2