diff mbox series

[v6,21/28] powerpc: Enable Prefixed Instructions

Message ID 20200428015814.15380-22-jniethe5@gmail.com (mailing list archive)
State Superseded
Headers show
Series Initial Prefixed Instruction support | expand

Checks

Context Check Description
snowpatch_ozlabs/apply_patch warning Failed to apply on branch powerpc/merge (54dc28ff5e0b3585224d49a31b53e030342ca5c3)
snowpatch_ozlabs/apply_patch warning Failed to apply on branch powerpc/next (45591da765885f7320a111d290b3a28a23eed359)
snowpatch_ozlabs/apply_patch warning Failed to apply on branch linus/master (51184ae37e0518fd90cb437a2fbc953ae558cd0d)
snowpatch_ozlabs/apply_patch warning Failed to apply on branch powerpc/fixes (5990cdee689c6885b27c6d969a3d58b09002b0bc)
snowpatch_ozlabs/apply_patch warning Failed to apply on branch linux-next (8bdabd09ec86a993419c8c98a4f34c12bc902c6c)
snowpatch_ozlabs/apply_patch fail Failed to apply to any branch

Commit Message

Jordan Niethe April 28, 2020, 1:58 a.m. UTC 
From: Alistair Popple <alistair@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 <npiggin@gmail.com>
Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Jordan Niethe <jniethe5@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 mbox series

Patch

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;