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From: Mark Brown <broonie@kernel.org>
To: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>
Cc: Julien Grall <julien@xen.org>,
	Zhang Lei <zhang.lei@jp.fujitsu.com>,
	Julien Grall <julien.grall@arm.com>,
	Mark Brown <broonie@kernel.org>,
	Dave Martin <Dave.Martin@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	Daniel Kiss <Daniel.Kiss@arm.com>
Subject: [PATCH v4 6/8] arm64/sve: Implement a helper to load SVE registers from FPSIMD state
Date: Fri, 28 Aug 2020 19:11:53 +0100	[thread overview]
Message-ID: <20200828181155.17745-7-broonie@kernel.org> (raw)
In-Reply-To: <20200828181155.17745-1-broonie@kernel.org>

From: Julien Grall <julien.grall@arm.com>

In a follow-up patch, we may save the FPSIMD rather than the full SVE
state when the state has to be zeroed on return to userspace (e.g
during a syscall).

Introduce an helper to load SVE vectors from FPSIMD state and zero the rest
of SVE registers.

Signed-off-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 arch/arm64/include/asm/fpsimd.h  |  2 ++
 arch/arm64/kernel/entry-fpsimd.S | 17 +++++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h
index 958f642e930d..bec5f14b622a 100644
--- a/arch/arm64/include/asm/fpsimd.h
+++ b/arch/arm64/include/asm/fpsimd.h
@@ -70,6 +70,8 @@ extern void sve_save_state(void *state, u32 *pfpsr);
 extern void sve_load_state(void const *state, u32 const *pfpsr,
 			   unsigned long vq_minus_1);
 extern void sve_flush_live(void);
+extern void sve_load_from_fpsimd_state(struct user_fpsimd_state const *state,
+				       unsigned long vq_minus_1);
 extern unsigned int sve_get_vl(void);
 
 struct arm64_cpu_capabilities;
diff --git a/arch/arm64/kernel/entry-fpsimd.S b/arch/arm64/kernel/entry-fpsimd.S
index fdf7a5a35c63..2ca395c25448 100644
--- a/arch/arm64/kernel/entry-fpsimd.S
+++ b/arch/arm64/kernel/entry-fpsimd.S
@@ -48,6 +48,23 @@ SYM_FUNC_START(sve_get_vl)
 	ret
 SYM_FUNC_END(sve_get_vl)
 
+/*
+ * Load SVE state from FPSIMD state.
+ *
+ * x0 = pointer to struct fpsimd_state
+ * x1 = VQ - 1
+ *
+ * Each SVE vector will be loaded with the first 128-bits taken from FPSIMD
+ * and the rest zeroed. All the other SVE registers will be zeroed.
+ */
+SYM_FUNC_START(sve_load_from_fpsimd_state)
+		sve_load_vq	x1, x2, x3
+		fpsimd_restore	x0, 8
+ _for n, 0, 15, _sve_pfalse	\n
+		_sve_wrffr	0
+		ret
+SYM_FUNC_END(sve_load_from_fpsimd_state)
+
 /* Zero all SVE registers but the first 128-bits of each vector */
 SYM_FUNC_START(sve_flush_live)
 	sve_flush
-- 
2.20.1


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  parent reply	other threads:[~2020-08-28 18:16 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-28 18:11 [PATCH v4 0/8] arm64/sve: First steps towards optimizing syscalls Mark Brown
2020-08-28 18:11 ` [PATCH v4 1/8] arm64/fpsimd: Update documentation of do_sve_acc Mark Brown
2020-08-28 18:11 ` [PATCH v4 2/8] arm64/signal: Update the comment in preserve_sve_context Mark Brown
2020-08-28 18:11 ` [PATCH v4 3/8] arm64/fpsimdmacros: Allow the macro "for" to be used in more cases Mark Brown
2020-09-21 12:38   ` Will Deacon
2020-09-21 16:53     ` Dave Martin
2020-09-21 18:09       ` Mark Brown
2020-09-22 13:51         ` Dave Martin
2020-09-22 13:59           ` Mark Brown
2020-09-22 14:07             ` Dave Martin
2020-08-28 18:11 ` [PATCH v4 4/8] arm64/fpsimdmacros: Introduce a macro to update ZCR_EL1.LEN Mark Brown
2020-08-28 18:11 ` [PATCH v4 5/8] arm64/sve: Implement a helper to flush SVE registers Mark Brown
2020-08-28 18:11 ` Mark Brown [this message]
2020-08-28 18:11 ` [PATCH v4 7/8] arm64/sve: Don't disable SVE on syscalls return Mark Brown
2020-09-21 12:36   ` Will Deacon
2020-09-21 18:03     ` Mark Brown
2020-09-22 14:03       ` Dave Martin
2020-09-22 16:04         ` Mark Brown
2020-08-28 18:11 ` [PATCH v4 8/8] arm64/sve: Rework SVE trap access to use TIF_SVE_NEEDS_FLUSH Mark Brown
2020-09-21 12:42 ` [PATCH v4 0/8] arm64/sve: First steps towards optimizing syscalls Will Deacon
2020-09-21 12:56   ` Mark Brown
2020-09-21 13:08     ` Will Deacon
2020-09-21 18:17 ` Will Deacon

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