This patch simply fix part of the documentation on the HTM code.
This fixes reference to old fields that were renamed in commit
000ec280e3dd ("powerpc: tm: Rename transct_(*) to ck(\1)_state").
It also documents better the flow after commit eb5c3f1c8647 ("powerpc:
Always save/restore checkpointed regs during treclaim/trecheckpoint"),
where tm_recheckpoint can recheckpoint what is in ck{fp,vr}_state blindly.
Signed-off-by: Breno Leitao <lei...@debian.org>
---
arch/powerpc/kernel/tm.S | 10 +++++-----
arch/powerpc/kernel/traps.c | 15 +++++++++------
2 files changed, 14 insertions(+), 11 deletions(-)
diff --git a/arch/powerpc/kernel/tm.S b/arch/powerpc/kernel/tm.S
index ff12f47a96b6..019d73053cd3 100644
--- a/arch/powerpc/kernel/tm.S
+++ b/arch/powerpc/kernel/tm.S
@@ -95,9 +95,9 @@ EXPORT_SYMBOL_GPL(tm_abort);
* uint8_t cause)
*
* - Performs a full reclaim. This destroys outstanding
- * transactions and updates thread->regs.tm_ckpt_* with the
- * original checkpointed state. Note that thread->regs is
- * unchanged.
+ * transactions and updates thread.ckpt_regs, thread.ckfp_state and
+ * thread.ckvr_state with the original checkpointed state. Note that
+ * thread->regs is unchanged.
*
* Purpose is to both abort transactions of, and preserve the state of,
* a transactions at a context switch. We preserve/restore both sets of process
@@ -260,7 +260,7 @@ _GLOBAL(tm_reclaim)
/* Altivec (VEC/VMX/VR)*/
addi r7, r3, THREAD_CKVRSTATE
- SAVE_32VRS(0, r6, r7) /* r6 scratch, r7 transact vr state */
+ SAVE_32VRS(0, r6, r7) /* r6 scratch, r7 ckvr_state */
mfvscr v0
li r6, VRSTATE_VSCR
stvx v0, r7, r6
@@ -271,7 +271,7 @@ _GLOBAL(tm_reclaim)
/* Floating Point (FP) */
addi r7, r3, THREAD_CKFPSTATE
- SAVE_32FPRS_VSRS(0, R6, R7) /* r6 scratch, r7 transact fp state */
+ SAVE_32FPRS_VSRS(0, R6, R7) /* r6 scratch, r7 ckfp_state */
mffs fr0
stfd fr0,FPSTATE_FPSCR(r7)
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 0e17dcb48720..6742b6b3eb37 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -1719,16 +1719,19 @@ void fp_unavailable_tm(struct pt_regs *regs)
* checkpointed FP registers need to be loaded.
*/
tm_reclaim_current(TM_CAUSE_FAC_UNAV);
- /* Reclaim didn't save out any FPRs to transact_fprs. */
+
+ /* Reclaim initially saved out bogus (lazy) FPRs to ckfp_state, and
+ * then it was overwrite by the thr->fp_state by tm_reclaim_thread().
+ *
+ * At this point, ck{fp,vr}_state contains the exact values we want to
+ * recheckpoint.
+ */
/* Enable FP for the task: */
current->thread.load_fp = 1;
- /* This loads and recheckpoints the FP registers from
- * thread.fpr[]. They will remain in registers after the
- * checkpoint so we don't need to reload them after.
- * If VMX is in use, the VRs now hold checkpointed values,
- * so we don't want to load the VRs from the thread_struct.
+ /*
+ * Recheckpoint all the checkpointed ckpt, ck{fp, vr}_state registers.
*/
tm_recheckpoint(¤t->thread);
}
--
2.16.3
