From: Alistair Popple <alist...@popple.id.au>
Prefix instructions have their own FSCR bit which needs to enabled via
a CPU feature. The kernel will save the FSCR for problem state but it
needs to be enabled initially.
If prefixed instructions are made unavailable by the [H]FSCR, attempting
to use them will cause a facility unavailable exception. Add "PREFIX" to
the facility_strings[].
Currently there are no prefixed instructions that are actually emulated
by emulate_instruction() within facility_unavailable_exception().
However, when caused by a prefixed instructions the SRR1 PREFIXED bit is
set. Prepare for dealing with emulated prefixed instructions by checking
for this bit.
Reviewed-by: Nicholas Piggin <npig...@gmail.com>
Signed-off-by: Alistair Popple <alist...@popple.id.au>
Signed-off-by: Jordan Niethe <jniet...@gmail.com>
---
v4:
- Squash "Check for prefixed instructions in
facility_unavailable_exception()" here
- Remove dt parts for now
---
arch/powerpc/include/asm/reg.h | 3 +++
arch/powerpc/kernel/traps.c | 1 +
2 files changed, 4 insertions(+)
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 1aa46dff0957..c7758c2ccc5f 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -397,6 +397,7 @@
#define SPRN_RWMR 0x375 /* Region-Weighting Mode Register */
/* HFSCR and FSCR bit numbers are the same */
+#define FSCR_PREFIX_LG 13 /* Enable Prefix Instructions */
#define FSCR_SCV_LG 12 /* Enable System Call Vectored */
#define FSCR_MSGP_LG 10 /* Enable MSGP */
#define FSCR_TAR_LG 8 /* Enable Target Address Register */
@@ -408,11 +409,13 @@
#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_PREFIX __MASK(FSCR_PREFIX_LG)
#define FSCR_SCV __MASK(FSCR_SCV_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_PREFIX __MASK(FSCR_PREFIX_LG)
#define HFSCR_MSGP __MASK(FSCR_MSGP_LG)
#define HFSCR_TAR __MASK(FSCR_TAR_LG)
#define HFSCR_EBB __MASK(FSCR_EBB_LG)
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 82a3438300fd..a4764b039749 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -1720,6 +1720,7 @@ void facility_unavailable_exception(struct pt_regs *regs)
[FSCR_TAR_LG] = "TAR",
[FSCR_MSGP_LG] = "MSGP",
[FSCR_SCV_LG] = "SCV",
+ [FSCR_PREFIX_LG] = "PREFIX",
};
char *facility = "unknown";
u64 value;
--
2.17.1
