2022-03-06 08:43:05

by Max Filippov

Subject: [PATCH 1/2] xtensa: rename PT_SIZE to PT_KERNEL_SIZE

PT_SIZE is used by the xtensa port to designate kernel exception frame
size. In preparation for struct pt_regs size change rename PT_SIZE to
PT_KERNEL_SIZE for clarity and change its definition to always cover
only the kernel exception frame.

Signed-off-by: Max Filippov <[email protected]>
---
arch/xtensa/kernel/asm-offsets.c | 2 +-
arch/xtensa/kernel/entry.S | 14 +++++++-------
arch/xtensa/kernel/vectors.S | 4 ++--
3 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/arch/xtensa/kernel/asm-offsets.c b/arch/xtensa/kernel/asm-offsets.c
index f1fd1390d069..37278e2785fb 100644
--- a/arch/xtensa/kernel/asm-offsets.c
+++ b/arch/xtensa/kernel/asm-offsets.c
@@ -63,7 +63,7 @@ int main(void)
DEFINE(PT_AREG15, offsetof (struct pt_regs, areg[15]));
DEFINE(PT_WINDOWBASE, offsetof (struct pt_regs, windowbase));
DEFINE(PT_WINDOWSTART, offsetof(struct pt_regs, windowstart));
- DEFINE(PT_SIZE, sizeof(struct pt_regs));
+ DEFINE(PT_KERNEL_SIZE, offsetof(struct pt_regs, areg[16]));
DEFINE(PT_AREG_END, offsetof (struct pt_regs, areg[XCHAL_NUM_AREGS]));
DEFINE(PT_USER_SIZE, offsetof(struct pt_regs, areg[XCHAL_NUM_AREGS]));
DEFINE(PT_XTREGS_OPT, offsetof(struct pt_regs, xtregs_opt));
diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S
index a1029a5b6a1d..77a7c8da3ff5 100644
--- a/arch/xtensa/kernel/entry.S
+++ b/arch/xtensa/kernel/entry.S
@@ -341,8 +341,8 @@ KABI_W _bbsi.l a2, 3, 1f
/* Copy spill slots of a0 and a1 to imitate movsp
* in order to keep exception stack continuous
*/
- l32i a3, a1, PT_SIZE
- l32i a0, a1, PT_SIZE + 4
+ l32i a3, a1, PT_KERNEL_SIZE
+ l32i a0, a1, PT_KERNEL_SIZE + 4
s32e a3, a1, -16
s32e a0, a1, -12
#endif
@@ -706,12 +706,12 @@ kernel_exception_exit:
addi a0, a1, -16
l32i a3, a0, 0
l32i a4, a0, 4
- s32i a3, a1, PT_SIZE+0
- s32i a4, a1, PT_SIZE+4
+ s32i a3, a1, PT_KERNEL_SIZE + 0
+ s32i a4, a1, PT_KERNEL_SIZE + 4
l32i a3, a0, 8
l32i a4, a0, 12
- s32i a3, a1, PT_SIZE+8
- s32i a4, a1, PT_SIZE+12
+ s32i a3, a1, PT_KERNEL_SIZE + 8
+ s32i a4, a1, PT_KERNEL_SIZE + 12

/* Common exception exit.
* We restore the special register and the current window frame, and
@@ -821,7 +821,7 @@ ENTRY(debug_exception)

bbsi.l a2, PS_UM_BIT, 2f # jump if user mode

- addi a2, a1, -16-PT_SIZE # assume kernel stack
+ addi a2, a1, -16 - PT_KERNEL_SIZE # assume kernel stack
3:
l32i a0, a3, DT_DEBUG_SAVE
s32i a1, a2, PT_AREG1
diff --git a/arch/xtensa/kernel/vectors.S b/arch/xtensa/kernel/vectors.S
index 407ece204e7c..1073fe4a584d 100644
--- a/arch/xtensa/kernel/vectors.S
+++ b/arch/xtensa/kernel/vectors.S
@@ -88,7 +88,7 @@ ENDPROC(_UserExceptionVector)
* Kernel exception vector. (Exceptions with PS.UM == 0, PS.EXCM == 0)
*
* We get this exception when we were already in kernel space.
- * We decrement the current stack pointer (kernel) by PT_SIZE and
+ * We decrement the current stack pointer (kernel) by PT_KERNEL_SIZE and
* jump to the first-level handler associated with the exception cause.
*
* Note: we need to preserve space for the spill region.
@@ -100,7 +100,7 @@ ENTRY(_KernelExceptionVector)

xsr a3, excsave1 # save a3, and get dispatch table
wsr a2, depc # save a2
- addi a2, a1, -16-PT_SIZE # adjust stack pointer
+ addi a2, a1, -16 - PT_KERNEL_SIZE # adjust stack pointer
s32i a0, a2, PT_AREG0 # save a0 to ESF
rsr a0, exccause # retrieve exception cause
s32i a0, a2, PT_DEPC # mark it as a regular exception
--
2.30.2

2022-03-08 10:27:01

by Kees Cook

Subject: Re: [PATCH 1/2] xtensa: rename PT_SIZE to PT_KERNEL_SIZE

On Sat, Mar 05, 2022 at 10:44:34PM -0800, Max Filippov wrote:
> PT_SIZE is used by the xtensa port to designate kernel exception frame
> size. In preparation for struct pt_regs size change rename PT_SIZE to
> PT_KERNEL_SIZE for clarity and change its definition to always cover
> only the kernel exception frame.
>
> Signed-off-by: Max Filippov <[email protected]>

Reviewed-by: Kees Cook <[email protected]>

--
Kees Cook