git: 79631b49eeda - stable/13 - arm: Fix handling of undefined instruction aborts in THUMB2 mode.

The branch stable/13 has been updated by mmel:

URL: https://cgit.FreeBSD.org/src/commit/?id=79631b49eeda47d90f6ceba9ad574e6625f1f2f1

commit 79631b49eeda47d90f6ceba9ad574e6625f1f2f1
Author:     Michal Meloun <mmel@FreeBSD.org>
AuthorDate: 2021-10-17 17:36:33 +0000
Commit:     Michal Meloun <mmel@FreeBSD.org>
CommitDate: 2022-01-20 10:12:36 +0000

    arm: Fix handling of undefined instruction aborts in THUMB2 mode.
    
    Correctly recognize NEON/SIMD and VFP instructions in THUMB2 mode and pass
    these to the appropriate handler. Note that it is not necessary to filter
    all undefined instruction variant or register combinations, this is a job
    for given handler.
    
    Reported by:    Robert Clausecker <fuz@fuz.su>
    PR:             259187
    MFC after:      2 weks
    
    (cherry picked from commit a670e1c13a522df4fb8c63bb023b88b1d65de797)
---
 sys/arm/arm/undefined.c | 39 +++++++++++++++++++++++----------------
 1 file changed, 23 insertions(+), 16 deletions(-)

diff --git a/sys/arm/arm/undefined.c b/sys/arm/arm/undefined.c
index ef9e72c89163..1fff398394fd 100644
--- a/sys/arm/arm/undefined.c
+++ b/sys/arm/arm/undefined.c
@@ -90,13 +90,25 @@ __FBSDID("$FreeBSD$");
 
 #define	ARM_COPROC_INSN(insn)	(((insn) & (1 << 27)) != 0)
 #define	ARM_VFP_INSN(insn)	((((insn) & 0xfe000000) == 0xf2000000) || \
-    (((insn) & 0xff100000) == 0xf4000000))
+				 (((insn) & 0xff100000) == 0xf4000000))
 #define	ARM_COPROC(insn)	(((insn) >> 8) & 0xf)
 
-#define	THUMB_32BIT_INSN(insn)	((insn) >= 0xe800)
+#define	THUMB_32BIT_INSN(insn)	((((insn) & 0xe000) == 0xe000) && \
+				 (((insn) & 0x1800) != 0))
+/*
+ * Coprocessor, Advanced SIMD, and
+ * Floating-point instructions on page A6-251
+ * OP1 == 01 OR 11
+ * OP2 == 1xxxxxx
+ */
 #define	THUMB_COPROC_INSN(insn)	(((insn) & (3 << 26)) == (3 << 26))
-#define	THUMB_COPROC_UNDEFINED(insn) (((insn) & 0x3e << 20) == 0)
-#define	THUMB_VFP_INSN(insn)	(((insn) & (3 << 24)) == (3 << 24))
+/*
+ * Advanced SIMD element or structure
+ * load/store instructions on page A7-275
+ * OP1 == 11
+ * OP2 == 001xxx0
+*/
+#define	THUMB_VFP_INSN(insn)	(((insn) & (0x1F1 << 20)) == (0x190 << 20))
 #define	THUMB_COPROC(insn)	(((insn) >> 8) & 0xf)
 
 #define	COPROC_VFP	10
@@ -278,18 +290,13 @@ undefinedinstruction(struct trapframe *frame)
 			fault_instruction <<= 16;
 			fault_instruction |= *(uint16_t *)(fault_pc + 2);
 
-			/*
-			 * Is it a Coprocessor, Advanced SIMD, or
-			 * Floating-point instruction.
-			 */
-			if (THUMB_COPROC_INSN(fault_instruction)) {
-				if (THUMB_COPROC_UNDEFINED(fault_instruction)) {
-					/* undefined insn */
-				} else if (THUMB_VFP_INSN(fault_instruction))
-					coprocessor = COPROC_VFP;
-				else
-					coprocessor =
-					    THUMB_COPROC(fault_instruction);
+			/* Coprocessor, Advanced SIMD and Floating-point */
+			if (THUMB_COPROC_INSN(fault_instruction))
+				coprocessor = THUMB_COPROC(fault_instruction);
+			else {
+				/* Advanced SIMD load/store */
+				if (THUMB_VFP_INSN(fault_instruction))
+					coprocessor = COPROC_VFP; /* SIMD */
 			}
 		}
 #else