Gustavo Romero <grom...@linux.ibm.com> writes:
> Althought AMR is stashed in the checkpoint area, currently we don't save
> it to the per thread checkpoint struct after a treclaim and so we don't
> restore it either from that struct when we trechkpt. As a consequence when
> the transaction is later rolled back the kernel space AMR value when the
> trechkpt was done appears in userspace.
>
> That commit saves and restores AMR accordingly on treclaim and trechkpt.
> Since AMR value is also used in kernel space in other functions, it also
> takes care of stashing kernel live AMR into the stack before treclaim and
> before trechkpt, restoring it later, just before returning from tm_reclaim
> and __tm_recheckpoint.
>
> Is also fixes two nonrelated comments about CR and MSR.
>
Tested-by: Aneesh Kumar K.V <aneesh.ku...@linux.ibm.com>
> Signed-off-by: Gustavo Romero <grom...@linux.ibm.com>
> ---
> arch/powerpc/include/asm/processor.h | 1 +
> arch/powerpc/kernel/asm-offsets.c | 1 +
> arch/powerpc/kernel/tm.S | 35 ++++++++++++++++++++++++----
> 3 files changed, 33 insertions(+), 4 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/processor.h
> b/arch/powerpc/include/asm/processor.h
> index ed0d633ab5aa..9f4f6cc033ac 100644
> --- a/arch/powerpc/include/asm/processor.h
> +++ b/arch/powerpc/include/asm/processor.h
> @@ -220,6 +220,7 @@ struct thread_struct {
> unsigned long tm_tar;
> unsigned long tm_ppr;
> unsigned long tm_dscr;
> + unsigned long tm_amr;
>
> /*
> * Checkpointed FP and VSX 0-31 register set.
> diff --git a/arch/powerpc/kernel/asm-offsets.c
> b/arch/powerpc/kernel/asm-offsets.c
> index 8711c2164b45..c2722ff36e98 100644
> --- a/arch/powerpc/kernel/asm-offsets.c
> +++ b/arch/powerpc/kernel/asm-offsets.c
> @@ -176,6 +176,7 @@ int main(void)
> OFFSET(THREAD_TM_TAR, thread_struct, tm_tar);
> OFFSET(THREAD_TM_PPR, thread_struct, tm_ppr);
> OFFSET(THREAD_TM_DSCR, thread_struct, tm_dscr);
> + OFFSET(THREAD_TM_AMR, thread_struct, tm_amr);
> OFFSET(PT_CKPT_REGS, thread_struct, ckpt_regs);
> OFFSET(THREAD_CKVRSTATE, thread_struct, ckvr_state.vr);
> OFFSET(THREAD_CKVRSAVE, thread_struct, ckvrsave);
> diff --git a/arch/powerpc/kernel/tm.S b/arch/powerpc/kernel/tm.S
> index 6ba0fdd1e7f8..2b91f233b05d 100644
> --- a/arch/powerpc/kernel/tm.S
> +++ b/arch/powerpc/kernel/tm.S
> @@ -122,6 +122,13 @@ _GLOBAL(tm_reclaim)
> std r3, STK_PARAM(R3)(r1)
> SAVE_NVGPRS(r1)
>
> + /*
> + * Save kernel live AMR since it will be clobbered by treclaim
> + * but can be used elsewhere later in kernel space.
> + */
> + mfspr r3, SPRN_AMR
> + std r3, TM_FRAME_L1(r1)
> +
> /* We need to setup MSR for VSX register save instructions. */
> mfmsr r14
> mr r15, r14
> @@ -245,7 +252,7 @@ _GLOBAL(tm_reclaim)
> * but is used in signal return to 'wind back' to the abort handler.
> */
>
> - /* ******************** CR,LR,CCR,MSR ********** */
> + /* ***************** CTR, LR, CR, XER ********** */
> mfctr r3
> mflr r4
> mfcr r5
> @@ -256,7 +263,6 @@ _GLOBAL(tm_reclaim)
> std r5, _CCR(r7)
> std r6, _XER(r7)
>
> -
> /* ******************** TAR, DSCR ********** */
> mfspr r3, SPRN_TAR
> mfspr r4, SPRN_DSCR
> @@ -264,6 +270,10 @@ _GLOBAL(tm_reclaim)
> std r3, THREAD_TM_TAR(r12)
> std r4, THREAD_TM_DSCR(r12)
>
> + /* ******************** AMR **************** */
> + mfspr r3, SPRN_AMR
> + std r3, THREAD_TM_AMR(r12)
> +
> /*
> * MSR and flags: We don't change CRs, and we don't need to alter MSR.
> */
> @@ -308,7 +318,9 @@ _GLOBAL(tm_reclaim)
> std r3, THREAD_TM_TFHAR(r12)
> std r4, THREAD_TM_TFIAR(r12)
>
> - /* AMR is checkpointed too, but is unsupported by Linux. */
> + /* Restore kernel live AMR */
> + ld r8, TM_FRAME_L1(r1)
> + mtspr SPRN_AMR, r8
>
> /* Restore original MSR/IRQ state & clear TM mode */
> ld r14, TM_FRAME_L0(r1) /* Orig MSR */
> @@ -355,6 +367,13 @@ _GLOBAL(__tm_recheckpoint)
> */
> SAVE_NVGPRS(r1)
>
> + /*
> + * Save kernel live AMR since it will be clobbered for trechkpt
> + * but can be used elsewhere later in kernel space.
> + */
> + mfspr r8, SPRN_AMR
> + std r8, TM_FRAME_L0(r1)
> +
> /* Load complete register state from ts_ckpt* registers */
>
> addi r7, r3, PT_CKPT_REGS /* Thread's ckpt_regs */
> @@ -404,7 +423,7 @@ _GLOBAL(__tm_recheckpoint)
>
> restore_gprs:
>
> - /* ******************** CR,LR,CCR,MSR ********** */
> + /* ****************** CTR, LR, XER ************* */
> ld r4, _CTR(r7)
> ld r5, _LINK(r7)
> ld r8, _XER(r7)
> @@ -417,6 +436,10 @@ restore_gprs:
> ld r4, THREAD_TM_TAR(r3)
> mtspr SPRN_TAR, r4
>
> + /* ******************** AMR ******************** */
> + ld r4, THREAD_TM_AMR(r3)
> + mtspr SPRN_AMR, r4
> +
> /* Load up the PPR and DSCR in GPRs only at this stage */
> ld r5, THREAD_TM_DSCR(r3)
> ld r6, THREAD_TM_PPR(r3)
> @@ -509,6 +532,10 @@ restore_gprs:
> li r4, MSR_RI
> mtmsrd r4, 1
>
> + /* Restore kernel live AMR */
> + ld r8, TM_FRAME_L0(r1)
> + mtspr SPRN_AMR, r8
> +
> REST_NVGPRS(r1)
>
> addi r1, r1, TM_FRAME_SIZE
> --
> 2.25.1
