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Commit 4e2bf01b authored by Michael Ellerman's avatar Michael Ellerman Committed by Benjamin Herrenschmidt
Browse files

powerpc: Move bad_stack() below the fwnmi_data_area 



At the moment the allmodconfig build is failing because we run out of
space between altivec_assist() at 0x5700 and the fwnmi_data_area at
0x7000.

Fixing it permanently will take some more work, but a quick fix is to
move bad_stack() below the fwnmi_data_area. That gives us just enough
room with everything enabled.

bad_stack() is called from the common exception handlers, but it's a
non-conditional branch, so we have plenty of scope to move it further
way.

Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 1e07a0a0

arch/powerpc/kernel/exceptions-64s.S

+60 −60
Original line number Diff line number Diff line
@@ -952,66 +952,6 @@ system_call_entry: 
ppc64_runlatch_on_trampoline:

	b	__ppc64_runlatch_on



/*

 * Here we have detected that the kernel stack pointer is bad.

 * R9 contains the saved CR, r13 points to the paca,

 * r10 contains the (bad) kernel stack pointer,

 * r11 and r12 contain the saved SRR0 and SRR1.

 * We switch to using an emergency stack, save the registers there,

 * and call kernel_bad_stack(), which panics.

 */

bad_stack:

	ld	r1,PACAEMERGSP(r13)

	subi	r1,r1,64+INT_FRAME_SIZE

	std	r9,_CCR(r1)

	std	r10,GPR1(r1)

	std	r11,_NIP(r1)

	std	r12,_MSR(r1)

	mfspr	r11,SPRN_DAR

	mfspr	r12,SPRN_DSISR

	std	r11,_DAR(r1)

	std	r12,_DSISR(r1)

	mflr	r10

	mfctr	r11

	mfxer	r12

	std	r10,_LINK(r1)

	std	r11,_CTR(r1)

	std	r12,_XER(r1)

	SAVE_GPR(0,r1)

	SAVE_GPR(2,r1)

	ld	r10,EX_R3(r3)

	std	r10,GPR3(r1)

	SAVE_GPR(4,r1)

	SAVE_4GPRS(5,r1)

	ld	r9,EX_R9(r3)

	ld	r10,EX_R10(r3)

	SAVE_2GPRS(9,r1)

	ld	r9,EX_R11(r3)

	ld	r10,EX_R12(r3)

	ld	r11,EX_R13(r3)

	std	r9,GPR11(r1)

	std	r10,GPR12(r1)

	std	r11,GPR13(r1)

BEGIN_FTR_SECTION

	ld	r10,EX_CFAR(r3)

	std	r10,ORIG_GPR3(r1)

END_FTR_SECTION_IFSET(CPU_FTR_CFAR)

	SAVE_8GPRS(14,r1)

	SAVE_10GPRS(22,r1)

	lhz	r12,PACA_TRAP_SAVE(r13)

	std	r12,_TRAP(r1)

	addi	r11,r1,INT_FRAME_SIZE

	std	r11,0(r1)

	li	r12,0

	std	r12,0(r11)

	ld	r2,PACATOC(r13)

	ld	r11,exception_marker@toc(r2)

	std	r12,RESULT(r1)

	std	r11,STACK_FRAME_OVERHEAD-16(r1)

1:	addi	r3,r1,STACK_FRAME_OVERHEAD

	bl	kernel_bad_stack

	b	1b



/*

 * Here r13 points to the paca, r9 contains the saved CR,

 * SRR0 and SRR1 are saved in r11 and r12,
@@ -1636,3 +1576,63 @@ handle_dabr_fault: 
	li	r5,SIGSEGV

	bl	bad_page_fault

	b	ret_from_except



/*

 * Here we have detected that the kernel stack pointer is bad.

 * R9 contains the saved CR, r13 points to the paca,

 * r10 contains the (bad) kernel stack pointer,

 * r11 and r12 contain the saved SRR0 and SRR1.

 * We switch to using an emergency stack, save the registers there,

 * and call kernel_bad_stack(), which panics.

 */

bad_stack:

	ld	r1,PACAEMERGSP(r13)

	subi	r1,r1,64+INT_FRAME_SIZE

	std	r9,_CCR(r1)

	std	r10,GPR1(r1)

	std	r11,_NIP(r1)

	std	r12,_MSR(r1)

	mfspr	r11,SPRN_DAR

	mfspr	r12,SPRN_DSISR

	std	r11,_DAR(r1)

	std	r12,_DSISR(r1)

	mflr	r10

	mfctr	r11

	mfxer	r12

	std	r10,_LINK(r1)

	std	r11,_CTR(r1)

	std	r12,_XER(r1)

	SAVE_GPR(0,r1)

	SAVE_GPR(2,r1)

	ld	r10,EX_R3(r3)

	std	r10,GPR3(r1)

	SAVE_GPR(4,r1)

	SAVE_4GPRS(5,r1)

	ld	r9,EX_R9(r3)

	ld	r10,EX_R10(r3)

	SAVE_2GPRS(9,r1)

	ld	r9,EX_R11(r3)

	ld	r10,EX_R12(r3)

	ld	r11,EX_R13(r3)

	std	r9,GPR11(r1)

	std	r10,GPR12(r1)

	std	r11,GPR13(r1)

BEGIN_FTR_SECTION

	ld	r10,EX_CFAR(r3)

	std	r10,ORIG_GPR3(r1)

END_FTR_SECTION_IFSET(CPU_FTR_CFAR)

	SAVE_8GPRS(14,r1)

	SAVE_10GPRS(22,r1)

	lhz	r12,PACA_TRAP_SAVE(r13)

	std	r12,_TRAP(r1)

	addi	r11,r1,INT_FRAME_SIZE

	std	r11,0(r1)

	li	r12,0

	std	r12,0(r11)

	ld	r2,PACATOC(r13)

	ld	r11,exception_marker@toc(r2)

	std	r12,RESULT(r1)

	std	r11,STACK_FRAME_OVERHEAD-16(r1)

1:	addi	r3,r1,STACK_FRAME_OVERHEAD

	bl	kernel_bad_stack

	b	1b