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| author | Max Filippov <jcmvbkbc@gmail.com> | 2016-03-06 23:36:33 +0100 |
|---|---|---|
| committer | Chris Zankel <chris@zankel.net> | 2016-03-11 09:53:32 +0100 |
| commit | 6ec7026ac01f3db039e0428db1f37590685ad3e7 (patch) | |
| tree | 9a3ac45e85c4ba604ce9dde4d14c103c9d2e70ff /arch/xtensa/kernel/entry.S | |
| parent | xtensa: remove remaining non-functional KGDB bits (diff) | |
| download | linux-6ec7026ac01f3db039e0428db1f37590685ad3e7.tar.xz linux-6ec7026ac01f3db039e0428db1f37590685ad3e7.zip | |
xtensa: use context structure for debug exceptions
With implementation of data breakpoints debug exceptions raised when
PS.EXCM is set need to be handled, e.g. window overflow code can write
to watched userspace address. Currently debug exception handler uses
EXCSAVE and DEPC SRs to save temporary registers, but DEPC may not be
available when PS.EXCM is set and more space will be needed to save
additional state.
Reorganize debug context: create per-CPU structure debug_table instance
and store its address in the EXCSAVE<debug level> instead of
debug_exception function address. Expand this structure when more save
space is needed.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Diffstat (limited to 'arch/xtensa/kernel/entry.S')
| -rw-r--r-- | arch/xtensa/kernel/entry.S | 20 |
1 files changed, 8 insertions, 12 deletions
diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S index db5c1765b413..ab7904fd027f 100644 --- a/arch/xtensa/kernel/entry.S +++ b/arch/xtensa/kernel/entry.S @@ -789,36 +789,32 @@ ENTRY(debug_exception) movi a2, 1 << PS_EXCM_BIT or a2, a0, a2 - movi a0, debug_exception # restore a3, debug jump vector wsr a2, ps - xsr a0, SREG_EXCSAVE + XCHAL_DEBUGLEVEL /* Switch to kernel/user stack, restore jump vector, and save a0 */ bbsi.l a2, PS_UM_BIT, 2f # jump if user mode addi a2, a1, -16-PT_SIZE # assume kernel stack +3: + l32i a0, a3, DT_DEBUG_SAVE + s32i a1, a2, PT_AREG1 s32i a0, a2, PT_AREG0 movi a0, 0 - s32i a1, a2, PT_AREG1 s32i a0, a2, PT_DEPC # mark it as a regular exception + xsr a3, SREG_EXCSAVE + XCHAL_DEBUGLEVEL xsr a0, depc s32i a3, a2, PT_AREG3 s32i a0, a2, PT_AREG2 mov a1, a2 + + rsr a2, ps + bbsi.l a2, PS_UM_BIT, _user_exception j _kernel_exception 2: rsr a2, excsave1 l32i a2, a2, EXC_TABLE_KSTK # load kernel stack pointer - s32i a0, a2, PT_AREG0 - movi a0, 0 - s32i a1, a2, PT_AREG1 - s32i a0, a2, PT_DEPC - xsr a0, depc - s32i a3, a2, PT_AREG3 - s32i a0, a2, PT_AREG2 - mov a1, a2 - j _user_exception + j 3b /* Debug exception while in exception mode. */ 1: j 1b // FIXME!! |