This enables new registers, LMRR and LMSER, that can trigger an EBB in
userspace code when a monitored load (via the new ldmx instruction)
loads memory from a monitored space. This facility is controlled by a
new FSCR bit, LM.
This patch disables the control bit on CPU setup and enables that bit
when a facility unavailable exception is taken for using it. On context
switch, this bit is then used to determine whether the two relevant
registers are saved and restored. This is done lazily for performance
reasons.
Signed-off-by: Jack Miller <j...@codezen.org>
---
arch/powerpc/include/asm/processor.h | 2 ++
arch/powerpc/include/asm/reg.h | 5 +++++
arch/powerpc/kernel/cpu_setup_power.S | 3 ++-
arch/powerpc/kernel/process.c | 19 +++++++++++++++++++
arch/powerpc/kernel/traps.c | 4 ++++
5 files changed, 32 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/processor.h
b/arch/powerpc/include/asm/processor.h
index 009fab1..2bb822b 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -314,6 +314,8 @@ struct thread_struct {
unsigned long mmcr2;
unsigned mmcr0;
unsigned used_ebb;
+ unsigned long lmrr;
+ unsigned long lmser;
#endif
};
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 7972c9f..ab98ca4 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -282,6 +282,8 @@
#define SPRN_HRMOR 0x139 /* Real mode offset register */
#define SPRN_HSRR0 0x13A /* Hypervisor Save/Restore 0 */
#define SPRN_HSRR1 0x13B /* Hypervisor Save/Restore 1 */
+#define SPRN_LMRR 0x32D /* Load Monitor Region Register */
+#define SPRN_LMSER 0x32E /* Load Monitor Section Enable Register */
#define SPRN_IC 0x350 /* Virtual Instruction Count */
#define SPRN_VTB 0x351 /* Virtual Time Base */
#define SPRN_LDBAR 0x352 /* LD Base Address Register */
@@ -291,6 +293,7 @@
#define SPRN_PMCR 0x374 /* Power Management Control Register */
/* HFSCR and FSCR bit numbers are the same */
+#define FSCR_LM_LG 11 /* Enable Load Monitor Registers */
#define FSCR_TAR_LG 8 /* Enable Target Address Register */
#define FSCR_EBB_LG 7 /* Enable Event Based Branching */
#define FSCR_TM_LG 5 /* Enable Transactional Memory */
@@ -300,10 +303,12 @@
#define FSCR_VECVSX_LG 1 /* Enable VMX/VSX */
#define FSCR_FP_LG 0 /* Enable Floating Point */
#define SPRN_FSCR 0x099 /* Facility Status & Control Register */
+#define FSCR_LM __MASK(FSCR_LM_LG)
#define FSCR_TAR __MASK(FSCR_TAR_LG)
#define FSCR_EBB __MASK(FSCR_EBB_LG)
#define FSCR_DSCR __MASK(FSCR_DSCR_LG)
#define SPRN_HFSCR 0xbe /* HV=1 Facility Status & Control Register */
+#define HFSCR_LM __MASK(FSCR_LM_LG)
#define HFSCR_TAR __MASK(FSCR_TAR_LG)
#define HFSCR_EBB __MASK(FSCR_EBB_LG)
#define HFSCR_TM __MASK(FSCR_TM_LG)
diff --git a/arch/powerpc/kernel/cpu_setup_power.S
b/arch/powerpc/kernel/cpu_setup_power.S
index 584e119..a232930 100644
--- a/arch/powerpc/kernel/cpu_setup_power.S
+++ b/arch/powerpc/kernel/cpu_setup_power.S
@@ -157,7 +157,8 @@ __init_LPCR:
__init_FSCR:
mfspr r3,SPRN_FSCR
- ori r3,r3,FSCR_TAR|FSCR_DSCR|FSCR_EBB
+ ori r3,r3,FSCR_LM|FSCR_TAR|FSCR_DSCR|FSCR_EBB
+ xori r3,r3,FSCR_LM
mtspr SPRN_FSCR,r3
blr
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 00bf6f5..3e91bd6 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1005,6 +1005,14 @@ static inline void save_sprs(struct thread_struct *t)
*/
t->tar = mfspr(SPRN_TAR);
}
+
+ if (cpu_has_feature(CPU_FTR_ARCH_300)) {
+ /* Conditionally save Load Monitor registers, if enabled */
+ if (t->fscr & FSCR_LM) {
+ t->lmrr = mfspr(SPRN_LMRR);
+ t->lmser = mfspr(SPRN_LMSER);
+ }
+ }
#endif
}
@@ -1041,6 +1049,16 @@ static inline void restore_sprs(struct thread_struct
*old_thread,
if (old_thread->tar != new_thread->tar)
mtspr(SPRN_TAR, new_thread->tar);
}
+
+ if (cpu_has_feature(CPU_FTR_ARCH_300)) {
+ /* Conditionally restore Load Monitor registers, if enabled */
+ if (new_thread->fscr & FSCR_LM) {
+ if (old_thread->lmrr != new_thread->lmrr);
+ mtspr(SPRN_LMRR, new_thread->lmrr);
+ if (old_thread->lmser != new_thread->lmser);
+ mtspr(SPRN_LMSER, new_thread->lmser);
+ }
+ }
#endif
}
@@ -1592,6 +1610,7 @@ void start_thread(struct pt_regs *regs, unsigned long
start, unsigned long sp)
current->thread.tm_texasr = 0;
current->thread.tm_tfiar = 0;
#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
+ current->thread.fscr &= ~FSCR_LM;
}
EXPORT_SYMBOL(start_thread);
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 9229ba6..93ff3ac 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -1376,6 +1376,7 @@ void facility_unavailable_exception(struct pt_regs *regs)
[FSCR_TM_LG] = "TM",
[FSCR_EBB_LG] = "EBB",
[FSCR_TAR_LG] = "TAR",
+ [FSCR_LM_LG] = "LM",
};
char *facility = "unknown";
u64 value;
@@ -1432,6 +1433,9 @@ void facility_unavailable_exception(struct pt_regs *regs)
emulate_single_step(regs);
}
return;
+ } else if ((status == FSCR_LM_LG) && cpu_has_feature(CPU_FTR_ARCH_300))
{
+ mtspr(SPRN_FSCR, value | FSCR_LM);
+ return;
}
if ((status < ARRAY_SIZE(facility_strings)) &&
--
2.8.0
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