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[-next,v17,15/20] riscv: signal: validate altstack to reflect Vector

Message ID 20230327164941.20491-16-andy.chiu@sifive.com (mailing list archive)
State Superseded
Headers show
Series riscv: Add vector ISA support | expand

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Commit Message

Andy Chiu March 27, 2023, 4:49 p.m. UTC 
Some extensions, such as Vector, dynamically change footprint on a
signal frame, so MINSIGSTKSZ is no longer accurate. For example, an
RV64V implementation with vlen = 512 may occupy 2K + 40 + 12 Bytes of a
signal frame with the upcoming support. And processes that do not
execute any vector instructions do not need to reserve the extra
sigframe. So we need a way to guard the allocation size of the sigframe
at process runtime according to current status of V.

Thus, provide the function sigaltstack_size_valid() to validate its size
based on current allocation status of supported extensions.

Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
---
 arch/riscv/kernel/signal.c | 7 +++++++
 1 file changed, 7 insertions(+)

Comments

Heiko Stuebner March 31, 2023, 1:43 p.m. UTC | #1 
Am Montag, 27. März 2023, 18:49:35 CEST schrieb Andy Chiu:
> Some extensions, such as Vector, dynamically change footprint on a
> signal frame, so MINSIGSTKSZ is no longer accurate. For example, an
> RV64V implementation with vlen = 512 may occupy 2K + 40 + 12 Bytes of a
> signal frame with the upcoming support. And processes that do not
> execute any vector instructions do not need to reserve the extra
> sigframe. So we need a way to guard the allocation size of the sigframe
> at process runtime according to current status of V.
> 
> Thus, provide the function sigaltstack_size_valid() to validate its size
> based on current allocation status of supported extensions.
> 
> Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
> Reviewed-by: Conor Dooley <conor.dooley@microchip.com>

Reviewed-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Tested-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
diff mbox series

Patch

diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c
index 40f740183768..11411e113f0e 100644
--- a/arch/riscv/kernel/signal.c
+++ b/arch/riscv/kernel/signal.c
@@ -469,3 +469,10 @@  void __init init_rt_signal_env(void)
 	 */
 	signal_minsigstksz = get_rt_frame_size(true);
 }
+
+#ifdef CONFIG_DYNAMIC_SIGFRAME
+bool sigaltstack_size_valid(size_t ss_size)
+{
+	return ss_size > get_rt_frame_size(false);
+}
+#endif /* CONFIG_DYNAMIC_SIGFRAME */