git: 10a93c92c40a - main - arm64: Remove an old workaround

The branch main has been updated by andrew:

URL: https://cgit.FreeBSD.org/src/commit/?id=10a93c92c40aab0fd3f24bf17005318b165b9ef4

commit 10a93c92c40aab0fd3f24bf17005318b165b9ef4
Author:     Andrew Turner <andrew@FreeBSD.org>
AuthorDate: 2025-05-12 11:05:58 +0000
Commit:     Andrew Turner <andrew@FreeBSD.org>
CommitDate: 2025-05-12 11:05:58 +0000

    arm64: Remove an old workaround
    
    This is an old workaround for an instruction that wasn't emulated
    correctly in some places. As we now read more ID registers that should
    also hit this bug trapping this register, and not the others we can
    assume nobody hits this anymore.
    
    Reviewed by:    harry.moulton_arm.com, imp, emaste
    Sponsored by:   Arm Ltd
    Differential Revision:  https://reviews.freebsd.org/D50204
---
 sys/arm64/arm64/undefined.c | 31 -------------------------------
 1 file changed, 31 deletions(-)

diff --git a/sys/arm64/arm64/undefined.c b/sys/arm64/arm64/undefined.c
index cdd2a083ec17..1f44114af544 100644
--- a/sys/arm64/arm64/undefined.c
+++ b/sys/arm64/arm64/undefined.c
@@ -88,36 +88,6 @@ struct undef_handler {
  */
 LIST_HEAD(, undef_handler) undef_handlers[2];
 
-/*
- * Work around a bug in QEMU prior to 2.5.1 where reading unknown ID
- * registers would raise an exception when they should return 0.
- */
-static int
-id_aa64mmfr2_handler(vm_offset_t va, uint32_t insn, struct trapframe *frame,
-    uint32_t esr)
-{
-	int reg;
-
-#define	 MRS_ID_AA64MMFR2_EL0_MASK	(MRS_MASK | 0x000fffe0)
-#define	 MRS_ID_AA64MMFR2_EL0_VALUE	(MRS_VALUE | 0x00080740)
-
-	/* mrs xn, id_aa64mfr2_el1 */
-	if ((insn & MRS_ID_AA64MMFR2_EL0_MASK) == MRS_ID_AA64MMFR2_EL0_VALUE) {
-		reg = MRS_REGISTER(insn);
-
-		frame->tf_elr += INSN_SIZE;
-		if (reg < nitems(frame->tf_x)) {
-			frame->tf_x[reg] = 0;
-		} else if (reg == 30) {
-			frame->tf_lr = 0;
-		}
-		/* If reg is 32 then write to xzr, i.e. do nothing */
-
-		return (1);
-	}
-	return (0);
-}
-
 static bool
 arm_cond_match(uint32_t insn, struct trapframe *frame)
 {
@@ -282,7 +252,6 @@ undef_init(void)
 	LIST_INIT(&undef_handlers[0]);
 	LIST_INIT(&undef_handlers[1]);
 
-	install_undef_handler(false, id_aa64mmfr2_handler);
 #ifdef COMPAT_FREEBSD32
 	install_undef_handler(true, gdb_trapper);
 	install_undef_handler(true, swp_emulate);