Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 fixes from Will Deacon:
 "Here is a (hopefully) final round of arm64 fixes for 6.12 that address
  some user-visible floating point register corruption. Both of the
  Marks have been working on this for a couple of weeks and we've ended
  up in a position where SVE is solid but SME still has enough pending
  issues that the most pragmatic solution for the release and stable
  backports is to disable the feature. Yes, it's a shame, but the
  hardware is rare as hen's teeth at the moment and we're better off
  getting back to a known good state before fixing it all properly.
  We're also improving the selftests for 6.13 to help avoid merging
  broken code in the future.

  Anyway, the good news is that we're removing a lot more code than
  we're adding.

  Summary:

   - Fix handling of SVE traps from userspace on preemptible kernels
     when converting the saved floating point state into SVE state.

   - Remove broken support for the SMCCCv1.3 "SVE discard hint"
     optimisation.

   - Disable SME support, as the current support code suffers from
     numerous issues around signal delivery, ptrace access and
     context-switch which can lead to user-visible corruption of the
     register state"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: Kconfig: Make SME depend on BROKEN for now
  arm64: smccc: Remove broken support for SMCCCv1.3 SVE discard hint
  arm64/sve: Discard stale CPU state when handling SVE traps

1 files changed, 3 insertions, 29 deletions

diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h
index f59099a213d0..67f6fdf2e7cd 100644
--- a/include/linux/arm-smccc.h
+++ b/include/linux/arm-smccc.h
@@ -315,8 +315,6 @@ u32 arm_smccc_get_version(void);
 
 void __init arm_smccc_version_init(u32 version, enum arm_smccc_conduit conduit);
 
-extern u64 smccc_has_sve_hint;
-
 /**
  * arm_smccc_get_soc_id_version()
  *
@@ -415,15 +413,6 @@ struct arm_smccc_quirk {
 };
 
 /**
- * __arm_smccc_sve_check() - Set the SVE hint bit when doing SMC calls
- *
- * Sets the SMCCC hint bit to indicate if there is live state in the SVE
- * registers, this modifies x0 in place and should never be called from C
- * code.
- */
-asmlinkage unsigned long __arm_smccc_sve_check(unsigned long x0);
-
-/**
  * __arm_smccc_smc() - make SMC calls
  * @a0-a7: arguments passed in registers 0 to 7
  * @res: result values from registers 0 to 3
@@ -490,20 +479,6 @@ asmlinkage void __arm_smccc_hvc(unsigned long a0, unsigned long a1,
 
 #endif
 
-/* nVHE hypervisor doesn't have a current thread so needs separate checks */
-#if defined(CONFIG_ARM64_SVE) && !defined(__KVM_NVHE_HYPERVISOR__)
-
-#define SMCCC_SVE_CHECK ALTERNATIVE("nop \n",  "bl __arm_smccc_sve_check \n", \
-				    ARM64_SVE)
-#define smccc_sve_clobbers "x16", "x30", "cc",
-
-#else
-
-#define SMCCC_SVE_CHECK
-#define smccc_sve_clobbers
-
-#endif
-
 #define __constraint_read_2	"r" (arg0)
 #define __constraint_read_3	__constraint_read_2, "r" (arg1)
 #define __constraint_read_4	__constraint_read_3, "r" (arg2)
@@ -574,12 +549,11 @@ asmlinkage void __arm_smccc_hvc(unsigned long a0, unsigned long a1,
 		register unsigned long r3 asm("r3"); 			\
 		CONCATENATE(__declare_arg_,				\
 			    COUNT_ARGS(__VA_ARGS__))(__VA_ARGS__);	\
-		asm volatile(SMCCC_SVE_CHECK				\
-			     inst "\n" :				\
+		asm volatile(inst "\n" :				\
 			     "=r" (r0), "=r" (r1), "=r" (r2), "=r" (r3)	\
 			     : CONCATENATE(__constraint_read_,		\
 					   COUNT_ARGS(__VA_ARGS__))	\
-			     : smccc_sve_clobbers "memory");		\
+			     : "memory");				\
 		if (___res)						\
 			*___res = (typeof(*___res)){r0, r1, r2, r3};	\
 	} while (0)
@@ -628,7 +602,7 @@ asmlinkage void __arm_smccc_hvc(unsigned long a0, unsigned long a1,
 		asm ("" :						\
 		     : CONCATENATE(__constraint_read_,			\
 				   COUNT_ARGS(__VA_ARGS__))		\
-		     : smccc_sve_clobbers "memory");			\
+		     : "memory");					\
 		if (___res)						\
 			___res->a0 = SMCCC_RET_NOT_SUPPORTED;		\
 	} while (0)