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Commit 529a86e0 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'ppc-bundle' (bundle from Michael Ellerman) 

Merge powerpc transactional memory fixes from Michael Ellerman:
 "I figured I'd still send you the commits using a bundle to make sure
  it works in case I need to do it again in future"

This fixes transactional memory state restore for powerpc.

* bundle'd patches from Michael Ellerman:
  powerpc/tm: Fix illegal TM state in signal handler
  powerpc/64s: Use emergency stack for kernel TM Bad Thing program checks
parents ff33952e 044215d1

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

+23 −1
Original line number Original line Diff line number Diff line
@@ -734,7 +734,29 @@ EXC_REAL(program_check, 0x700, 0x100) 
EXC_VIRT(program_check, 0x4700, 0x100, 0x700)

EXC_VIRT(program_check, 0x4700, 0x100, 0x700)

TRAMP_KVM(PACA_EXGEN, 0x700)

TRAMP_KVM(PACA_EXGEN, 0x700)

EXC_COMMON_BEGIN(program_check_common)

EXC_COMMON_BEGIN(program_check_common)

	EXCEPTION_PROLOG_COMMON(0x700, PACA_EXGEN)

	/*

	 * It's possible to receive a TM Bad Thing type program check with

	 * userspace register values (in particular r1), but with SRR1 reporting

	 * that we came from the kernel. Normally that would confuse the bad

	 * stack logic, and we would report a bad kernel stack pointer. Instead

	 * we switch to the emergency stack if we're taking a TM Bad Thing from

	 * the kernel.

	 */

	li	r10,MSR_PR		/* Build a mask of MSR_PR ..	*/

	oris	r10,r10,0x200000@h	/* .. and SRR1_PROGTM		*/

	and	r10,r10,r12		/* Mask SRR1 with that.		*/

	srdi	r10,r10,8		/* Shift it so we can compare	*/

	cmpldi	r10,(0x200000 >> 8)	/* .. with an immediate.	*/

	bne 1f				/* If != go to normal path.	*/



	/* SRR1 had PR=0 and SRR1_PROGTM=1, so use the emergency stack	*/

	andi.	r10,r12,MSR_PR;		/* Set CR0 correctly for label	*/

					/* 3 in EXCEPTION_PROLOG_COMMON	*/

	mr	r10,r1			/* Save r1			*/

	ld	r1,PACAEMERGSP(r13)	/* Use emergency stack		*/

	subi	r1,r1,INT_FRAME_SIZE	/* alloc stack frame		*/

	b 3f				/* Jump into the macro !!	*/

1:	EXCEPTION_PROLOG_COMMON(0x700, PACA_EXGEN)

	bl	save_nvgprs

	bl	save_nvgprs

	RECONCILE_IRQ_STATE(r10, r11)

	RECONCILE_IRQ_STATE(r10, r11)

	addi	r3,r1,STACK_FRAME_OVERHEAD

	addi	r3,r1,STACK_FRAME_OVERHEAD

arch/powerpc/kernel/signal_64.c

+12 −1
Original line number Original line Diff line number Diff line
@@ -452,9 +452,20 @@ static long restore_tm_sigcontexts(struct task_struct *tsk, 
	if (MSR_TM_RESV(msr))

	if (MSR_TM_RESV(msr))

		return -EINVAL;

		return -EINVAL;





	/* pull in MSR TM from user context */

	/* pull in MSR TS bits from user context */

	regs->msr = (regs->msr & ~MSR_TS_MASK) | (msr & MSR_TS_MASK);

	regs->msr = (regs->msr & ~MSR_TS_MASK) | (msr & MSR_TS_MASK);





	/*

	 * Ensure that TM is enabled in regs->msr before we leave the signal

	 * handler. It could be the case that (a) user disabled the TM bit

	 * through the manipulation of the MSR bits in uc_mcontext or (b) the

	 * TM bit was disabled because a sufficient number of context switches

	 * happened whilst in the signal handler and load_tm overflowed,

	 * disabling the TM bit. In either case we can end up with an illegal

	 * TM state leading to a TM Bad Thing when we return to userspace.

	 */

	regs->msr |= MSR_TM;



	/* pull in MSR LE from user context */

	/* pull in MSR LE from user context */

	regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE);

	regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE);