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Subject[PATCHv5 05/21] arm64: move sve_user_{enable,disable} to <asm/fpsimd.h>
Date
In subsequent patches, we'll want to make use of sve_user_enable() and
sve_user_disable() outside of kernel/fpsimd.c. Let's move these to
<asm/fpsimd.h> where we can make use of them.

To avoid ifdeffery in sequences like:

if (system_supports_sve() && some_condition)
sve_user_disable();

... empty stubs are provided when support for SVE is not enabled. Note
that system_supports_sve() contains as IS_ENABLED(CONFIG_ARM64_SVE), so
the sve_user_disable() call should be optimized away entirely when
CONFIG_ARM64_SVE is not selected.

To ensure that this is the case, the stub definitions contain a
BUILD_BUG(), as we do for other stubs for which calls should always be
optimized away when the relevant config option is not selected.

At the same time, the include list of <asm/fpsimd.h> is sorted while
adding <asm/sysreg.h>.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Dave Martin <dave.martin@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
---
arch/arm64/include/asm/fpsimd.h | 17 ++++++++++++++++-
arch/arm64/kernel/fpsimd.c | 10 ----------
2 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h
index fa92747a49c8..dd1ad3950ef5 100644
--- a/arch/arm64/include/asm/fpsimd.h
+++ b/arch/arm64/include/asm/fpsimd.h
@@ -16,13 +16,15 @@
#ifndef __ASM_FP_H
#define __ASM_FP_H

-#include <asm/ptrace.h>
#include <asm/errno.h>
+#include <asm/ptrace.h>
#include <asm/processor.h>
#include <asm/sigcontext.h>
+#include <asm/sysreg.h>

#ifndef __ASSEMBLY__

+#include <linux/build_bug.h>
#include <linux/cache.h>
#include <linux/init.h>
#include <linux/stddef.h>
@@ -102,6 +104,16 @@ extern int sve_set_vector_length(struct task_struct *task,
extern int sve_set_current_vl(unsigned long arg);
extern int sve_get_current_vl(void);

+static inline void sve_user_disable(void)
+{
+ sysreg_clear_set(cpacr_el1, CPACR_EL1_ZEN_EL0EN, 0);
+}
+
+static inline void sve_user_enable(void)
+{
+ sysreg_clear_set(cpacr_el1, 0, CPACR_EL1_ZEN_EL0EN);
+}
+
/*
* Probing and setup functions.
* Calls to these functions must be serialised with one another.
@@ -128,6 +140,9 @@ static inline int sve_get_current_vl(void)
return -EINVAL;
}

+static inline void sve_user_disable(void) { BUILD_BUG(); }
+static inline void sve_user_enable(void) { BUILD_BUG(); }
+
static inline void sve_init_vq_map(void) { }
static inline void sve_update_vq_map(void) { }
static inline int sve_verify_vq_map(void) { return 0; }
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index a98a7f96aff1..58c53bc96928 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -159,16 +159,6 @@ static void sve_free(struct task_struct *task)
__sve_free(task);
}

-static void sve_user_disable(void)
-{
- sysreg_clear_set(cpacr_el1, CPACR_EL1_ZEN_EL0EN, 0);
-}
-
-static void sve_user_enable(void)
-{
- sysreg_clear_set(cpacr_el1, 0, CPACR_EL1_ZEN_EL0EN);
-}
-
/*
* TIF_SVE controls whether a task can use SVE without trapping while
* in userspace, and also the way a task's FPSIMD/SVE state is stored
--
2.11.0
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