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

Pull arm64 fixes from Will Deacon:
 "I think the main one is fixing the dynamic SCS patching when full LTO
  is enabled (clang was silently getting this horribly wrong), but it's
  all good stuff.

  Rob just pointed out that the fix to the workaround for erratum
  #2966298 might not be necessary, but in the worst case it's harmless
  and since the official description leaves a little to be desired here,
  I've left it in.

  Summary:

   - Fix shadow call stack patching with LTO=full

   - Fix voluntary preemption of the FPSIMD registers from assembly code

   - Fix workaround for A520 CPU erratum #2966298 and extend to A510

   - Fix SME issues that resulted in corruption of the register state

   - Minor fixes (missing includes, formatting)"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: Fix silcon-errata.rst formatting
  arm64/sme: Always exit sme_alloc() early with existing storage
  arm64/fpsimd: Remove spurious check for SVE support
  arm64/ptrace: Don't flush ZA/ZT storage when writing ZA via ptrace
  arm64: entry: simplify kernel_exit logic
  arm64: entry: fix ARM64_WORKAROUND_SPECULATIVE_UNPRIV_LOAD
  arm64: errata: Add Cortex-A510 speculative unprivileged load workaround
  arm64: Rename ARM64_WORKAROUND_2966298
  arm64: fpsimd: Bring cond_yield asm macro in line with new rules
  arm64: scs: Work around full LTO issue with dynamic SCS
  arm64: irq: include <linux/cpumask.h>

2 files changed, 11 insertions, 16 deletions

diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index 7b1975bf4b90..513787e43329 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -760,32 +760,25 @@ alternative_endif
 .endm
 
 	/*
-	 * Check whether preempt/bh-disabled asm code should yield as soon as
-	 * it is able. This is the case if we are currently running in task
-	 * context, and either a softirq is pending, or the TIF_NEED_RESCHED
-	 * flag is set and re-enabling preemption a single time would result in
-	 * a preempt count of zero. (Note that the TIF_NEED_RESCHED flag is
-	 * stored negated in the top word of the thread_info::preempt_count
+	 * Check whether asm code should yield as soon as it is able. This is
+	 * the case if we are currently running in task context, and the
+	 * TIF_NEED_RESCHED flag is set. (Note that the TIF_NEED_RESCHED flag
+	 * is stored negated in the top word of the thread_info::preempt_count
 	 * field)
 	 */
-	.macro		cond_yield, lbl:req, tmp:req, tmp2:req
+	.macro		cond_yield, lbl:req, tmp:req, tmp2
+#ifdef CONFIG_PREEMPT_VOLUNTARY
 	get_current_task \tmp
 	ldr		\tmp, [\tmp, #TSK_TI_PREEMPT]
 	/*
 	 * If we are serving a softirq, there is no point in yielding: the
 	 * softirq will not be preempted no matter what we do, so we should
-	 * run to completion as quickly as we can.
+	 * run to completion as quickly as we can. The preempt_count field will
+	 * have BIT(SOFTIRQ_SHIFT) set in this case, so the zero check will
+	 * catch this case too.
 	 */
-	tbnz		\tmp, #SOFTIRQ_SHIFT, .Lnoyield_\@
-#ifdef CONFIG_PREEMPTION
-	sub		\tmp, \tmp, #PREEMPT_DISABLE_OFFSET
 	cbz		\tmp, \lbl
 #endif
-	adr_l		\tmp, irq_stat + IRQ_CPUSTAT_SOFTIRQ_PENDING
-	get_this_cpu_offset	\tmp2
-	ldr		w\tmp, [\tmp, \tmp2]
-	cbnz		w\tmp, \lbl	// yield on pending softirq in task context
-.Lnoyield_\@:
 	.endm
 
 /*
diff --git a/arch/arm64/include/asm/irq.h b/arch/arm64/include/asm/irq.h
index 50ce8b697ff3..e93548914c36 100644
--- a/arch/arm64/include/asm/irq.h
+++ b/arch/arm64/include/asm/irq.h
@@ -4,6 +4,8 @@
 
 #ifndef __ASSEMBLER__
 
+#include <linux/cpumask.h>
+
 #include <asm-generic/irq.h>
 
 void arch_trigger_cpumask_backtrace(const cpumask_t *mask, int exclude_cpu);