[v2,3/3] riscv: Call riscv_user_isa_enable() only on the boot hart

Commit Message

Samuel Holland June 13, 2024, 5:14 p.m. UTC

Now that the [ms]envcfg CSR value is maintained per thread, not per
hart, riscv_user_isa_enable() only needs to be called once during boot,
to set the value for the init task. This also allows it to be marked as
__init. riscv_isa_extension_check() sets any_cpu_has_zicboz, so it also
needs to be marked __init; it could have had this annotation already.

Reviewed-by: Deepak Gupta <[e-mail]>
Signed-off-by: Samuel Holland <[e-mail]>
---

Changes in v2:
 - Rebase on riscv/linux.git for-next

 arch/riscv/include/asm/cpufeature.h | 2 +-
 arch/riscv/kernel/cpufeature.c      | 8 ++++----
 arch/riscv/kernel/smpboot.c         | 2 --
 3 files changed, 5 insertions(+), 7 deletions(-)

Comments

Conor Dooley June 14, 2024, 10:32 a.m. UTC | #1

On Thu, Jun 13, 2024 at 10:14:41AM -0700, Samuel Holland wrote:
> Now that the [ms]envcfg CSR value is maintained per thread, not per
> hart, riscv_user_isa_enable() only needs to be called once during boot,
> to set the value for the init task. This also allows it to be marked as
> __init. riscv_isa_extension_check() sets any_cpu_has_zicboz, so it also
> needs to be marked __init; it could have had this annotation already.
> 
> Reviewed-by: Deepak Gupta <[e-mail]>
> Signed-off-by: Samuel Holland <[e-mail]>

Reviewed-by: Conor Dooley <[e-mail]>

Patch

diff --git a/arch/riscv/include/asm/cpufeature.h b/arch/riscv/include/asm/cpufeature.h
index 347805446151..4bf7b7ebf6b3 100644
--- a/arch/riscv/include/asm/cpufeature.h
+++ b/arch/riscv/include/asm/cpufeature.h
@@ -31,7 +31,7 @@  DECLARE_PER_CPU(struct riscv_cpuinfo, riscv_cpuinfo);
 /* Per-cpu ISA extensions. */
 extern struct riscv_isainfo hart_isa[NR_CPUS];
 
-void riscv_user_isa_enable(void);
+void __init riscv_user_isa_enable(void);
 
 #if defined(CONFIG_RISCV_MISALIGNED)
 bool check_unaligned_access_emulated_all_cpus(void);
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index b5b8773c57e8..d3e3a865b874 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -27,7 +27,7 @@ 
 
 #define NUM_ALPHA_EXTS ('z' - 'a' + 1)
 
-static bool any_cpu_has_zicboz;
+static bool any_cpu_has_zicboz __initdata;
 
 unsigned long elf_hwcap __read_mostly;
 
@@ -74,7 +74,7 @@  bool __riscv_isa_extension_available(const unsigned long *isa_bitmap, unsigned i
 }
 EXPORT_SYMBOL_GPL(__riscv_isa_extension_available);
 
-static bool riscv_isa_extension_check(int id)
+static bool __init riscv_isa_extension_check(int id)
 {
 	switch (id) {
 	case RISCV_ISA_EXT_ZICBOM:
@@ -769,12 +769,12 @@  unsigned long riscv_get_elf_hwcap(void)
 	return hwcap;
 }
 
-void riscv_user_isa_enable(void)
+void __init riscv_user_isa_enable(void)
 {
 	if (riscv_has_extension_unlikely(RISCV_ISA_EXT_ZICBOZ))
 		current->thread.envcfg |= ENVCFG_CBZE;
 	else if (any_cpu_has_zicboz)
-		pr_warn_once("Zicboz disabled as it is unavailable on some harts\n");
+		pr_warn("Zicboz disabled as it is unavailable on some harts\n");
 }
 
 #ifdef CONFIG_RISCV_ALTERNATIVE
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index 19baf0d574d3..0646f79e0a02 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -235,8 +235,6 @@  asmlinkage __visible void smp_callin(void)
 	numa_add_cpu(curr_cpuid);
 	set_cpu_online(curr_cpuid, true);
 
-	riscv_user_isa_enable();
-
 	/*
 	 * Remote cache and TLB flushes are ignored while the CPU is offline,
 	 * so flush them both right now just in case.