[RFC PATCH 02/36] arm64: debug: don't mask DAIF for mdscr_write()

Vladimir Murzin vladimir.murzin at arm.com
Thu Jul 9 05:12:59 PDT 2026


From: Ada Couprie Diaz <ada.coupriediaz at arm.com>

Masking DAIF around the write to MDSCR_EL1 doesn't do anything: we can
write to sysregs with interrupts unmasked, and writing to PSTATE is
not a context synchronization event so it does not synchronize it.

This is done in the context of a general interrupt handling cleanup,
so it does not address the missing context synchronization for the
MDSCR_EL1 write, staying consistent with the current state.  This
should be addressed in a future patch.

Signed-off-by: Ada Couprie Diaz <ada.coupriediaz at arm.com>
Signed-off-by: Vladimir Murzin <vladimir.murzin at arm.com>
---
 arch/arm64/kernel/debug-monitors.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c
index 29307642f4c9..e271fbac5f82 100644
--- a/arch/arm64/kernel/debug-monitors.c
+++ b/arch/arm64/kernel/debug-monitors.c
@@ -40,10 +40,7 @@ u8 debug_monitors_arch(void)
  */
 static void mdscr_write(u64 mdscr)
 {
-	unsigned long flags;
-	flags = local_daif_save();
 	write_sysreg(mdscr, mdscr_el1);
-	local_daif_restore(flags);
 }
 NOKPROBE_SYMBOL(mdscr_write);
 
-- 
2.34.1




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