Commit 6f291a03 authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Michael Ellerman
Browse files

powerpc: add a define for the switch frame size and regs offset 



This is open-coded in process.c, ppc32 uses a different define with the
same value, and the C definition is name differently which makes it an
extra indirection to grep for.

Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221127124942.1665522-12-npiggin@gmail.com
parent 1223e5a2

arch/powerpc/include/asm/ptrace.h

+4 −2
Original line number Diff line number Diff line
@@ -97,8 +97,6 @@ struct pt_regs 
#endif





#define STACK_FRAME_WITH_PT_REGS (STACK_FRAME_OVERHEAD + sizeof(struct pt_regs))



// Always displays as "REGS" in memory dumps

#ifdef CONFIG_CPU_BIG_ENDIAN

#define STACK_FRAME_REGS_MARKER	ASM_CONST(0x52454753)
@@ -125,6 +123,8 @@ struct pt_regs 
#define STACK_USER_INT_FRAME_SIZE	(sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD)

#define STACK_INT_FRAME_REGS	STACK_FRAME_OVERHEAD

#define STACK_INT_FRAME_MARKER	(STACK_FRAME_OVERHEAD - 16)

#define STACK_SWITCH_FRAME_SIZE	(sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD)

#define STACK_SWITCH_FRAME_REGS	STACK_FRAME_OVERHEAD



#ifdef CONFIG_PPC64_ELF_ABI_V2

#define STACK_FRAME_MIN_SIZE	32
@@ -146,6 +146,8 @@ struct pt_regs 
#define STACK_INT_FRAME_REGS	STACK_FRAME_OVERHEAD

#define STACK_INT_FRAME_MARKER	(STACK_FRAME_OVERHEAD - 8)

#define STACK_FRAME_MIN_SIZE	STACK_FRAME_OVERHEAD

#define STACK_SWITCH_FRAME_SIZE	(sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD)

#define STACK_SWITCH_FRAME_REGS	STACK_FRAME_OVERHEAD



/* Size of stack frame allocated when calling signal handler. */

#define __SIGNAL_FRAMESIZE	64

arch/powerpc/kernel/asm-offsets.c

+1 −1
Original line number Diff line number Diff line
@@ -260,7 +260,7 @@ int main(void) 


	/* Interrupt register frame */

	DEFINE(INT_FRAME_SIZE, STACK_INT_FRAME_SIZE);

	DEFINE(SWITCH_FRAME_SIZE, STACK_FRAME_WITH_PT_REGS);

	DEFINE(SWITCH_FRAME_SIZE, STACK_SWITCH_FRAME_SIZE);

	STACK_PT_REGS_OFFSET(GPR0, gpr[0]);

	STACK_PT_REGS_OFFSET(GPR1, gpr[1]);

	STACK_PT_REGS_OFFSET(GPR2, gpr[2]);

arch/powerpc/kernel/entry_32.S

+3 −3
Original line number Diff line number Diff line
@@ -215,9 +215,9 @@ ret_from_kernel_thread: 
 * in arch/ppc/kernel/process.c

 */

_GLOBAL(_switch)

	stwu	r1,-INT_FRAME_SIZE(r1)

	stwu	r1,-SWITCH_FRAME_SIZE(r1)

	mflr	r0

	stw	r0,INT_FRAME_SIZE+4(r1)

	stw	r0,SWITCH_FRAME_SIZE+4(r1)

	/* r3-r12 are caller saved -- Cort */

	SAVE_NVGPRS(r1)

	stw	r0,_NIP(r1)	/* Return to switch caller */
@@ -248,7 +248,7 @@ _GLOBAL(_switch) 


	lwz	r4,_NIP(r1)	/* Return to _switch caller in new task */

	mtlr	r4

	addi	r1,r1,INT_FRAME_SIZE

	addi	r1,r1,SWITCH_FRAME_SIZE

	blr



	.globl	fast_exception_return

arch/powerpc/kernel/process.c

+8 −4
Original line number Diff line number Diff line
@@ -1808,10 +1808,10 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) 
	 * do some house keeping and then return from the fork or clone

	 * system call, using the stack frame created above.

	 */

	sp -= sizeof(struct pt_regs);

	kregs = (struct pt_regs *) sp;

	sp -= STACK_FRAME_OVERHEAD;

	sp -= STACK_SWITCH_FRAME_SIZE;

	kregs = (struct pt_regs *)(sp + STACK_SWITCH_FRAME_REGS);

	p->thread.ksp = sp;



#ifdef CONFIG_HAVE_HW_BREAKPOINT

	for (i = 0; i < nr_wp_slots(); i++)

		p->thread.ptrace_bps[i] = NULL;
@@ -2261,8 +2261,12 @@ void __no_sanitize_address show_stack(struct task_struct *tsk, 
		/*

		 * See if this is an exception frame.

		 * We look for the "regs" marker in the current frame.

		 *

		 * STACK_SWITCH_FRAME_SIZE being the smallest frame that

		 * could hold a pt_regs, if that does not fit then it can't

		 * have regs.

		 */

		if (validate_sp(sp, tsk, STACK_FRAME_WITH_PT_REGS)

		if (validate_sp(sp, tsk, STACK_SWITCH_FRAME_SIZE)

		    && stack[STACK_INT_FRAME_MARKER_LONGS] == STACK_FRAME_REGS_MARKER) {

			struct pt_regs *regs = (struct pt_regs *)

				(sp + STACK_INT_FRAME_REGS);