powerpc/64: Fix setting of AIL in hypervisor mode

PATCH Applied Benjamin Herrenschmidt 3 participants 3 messages Nov 15, 2016 – Nov 17, 2016 PowerPC

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Benjamin Herrenschmidt

author

2016-11-15 04:28 UTC #0 lore raw

PATCH 1/1 powerpc/64: Fix setting of AIL in hypervisor mode

Commit d3cbff1b5 "powerpc: Put exception configuration in a common place" broke the setting of the AIL bit (which enables taking exceptions with the MMU still on) on all processors, moving it incorrectly to a function called only on the boot CPU. This was correct for the guest case but not when running in hypervisor mode.

This fixes it by partially reverting that commit, putting the setting back in cpu_ready_for_interrupts()

Signed-off-by Benjamin Herrenschmidt <[email protected]>

Fixes d3cbff1b5 ("powerpc: Put exception configuration in a common place")

CC [email protected] # v4.8+

---
 arch/powerpc/kernel/setup_64.c | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

arch/powerpc/kernel/setup_64.c +14 -6

index 7ac8e6e..ac75224 100644
@@ -226,17 +226,25 @@ static void __init configure_exceptions(void)
 		if (firmware_has_feature(FW_FEATURE_OPAL))
 			opal_configure_cores();
 
-		/* Enable AIL if supported, and we are in hypervisor mode */
-		if (early_cpu_has_feature(CPU_FTR_HVMODE) &&
-		    early_cpu_has_feature(CPU_FTR_ARCH_207S)) {
-			unsigned long lpcr = mfspr(SPRN_LPCR);
-			mtspr(SPRN_LPCR, lpcr | LPCR_AIL_3);
-		}
+		/* AIL on native is done in cpu_ready_for_interrupts */
 	}
 }
 
 static void cpu_ready_for_interrupts(void)
 {
+	/*
+	 * Enable AIL if supported, and we are in hypervisor mode. This
+	 * is called once for every processor.
+	 *
+	 * If we are not in hypervisor mode the job is done once for
+	 * the whole partition in configure_exceptions().
+	 */
+	if (early_cpu_has_feature(CPU_FTR_HVMODE) &&
+	    early_cpu_has_feature(CPU_FTR_ARCH_207S)) {
+		unsigned long lpcr = mfspr(SPRN_LPCR);
+		mtspr(SPRN_LPCR, lpcr | LPCR_AIL_3);
+	}
+
 	/* Set IR and DR in PACA MSR */
 	get_paca()->kernel_msr = MSR_KERNEL;
 }

Michael Ellerman

Applied

2016-11-17 05:00 UTC #1 lore raw

Quoted 6 lines · Benjamin Herrenschmidt

Commit d3cbff1b5 "powerpc: Put exception configuration in a common place" broke the setting of the AIL bit (which enables taking exceptions with the MMU still on) on all processors, moving it incorrectly to a function called only on the boot CPU. This was correct for the guest case but not when running in hypervisor mode.

Quoted 6 lines

This fixes it by partially reverting that commit, putting the setting back in cpu_ready_for_interrupts()
Signed-off-by Benjamin Herrenschmidt <[email protected]>
Fixes d3cbff1b5 ("powerpc: Put exception configuration in a common place")
CC [email protected] # v4.8+

Applied to powerpc fixes, thanks.

https://git.kernel.org/powerpc/c/c0a36013639b06760f7c2c21a8387e

cheers

Michael Neuling

Acked-by on v1 1/1

2016-11-17 22:38 UTC #2 lore raw

In reply to Benjamin Herrenschmidt

Quoted 11 lines · Benjamin Herrenschmidt

Commit d3cbff1b5 "powerpc: Put exception configuration in a common place" broke the setting of the AIL bit (which enables taking exceptions with the MMU still on) on all processors, moving it incorrectly to a function called only on the boot CPU. This was correct for the guest case but not when running in hypervisor mode.
=20
This fixes it by partially reverting that commit, putting the setting back in cpu_ready_for_interrupts()
=20
Signed-off-by Benjamin Herrenschmidt <[email protected]>
Fixes d3cbff1b5 ("powerpc: Put exception configuration in a common place=

Quoted 1 line

CC [email protected] # v4.8+

Acked-by Michael Neuling <[email protected]>

arch/powerpc/kernel/setup_6=

Quoted 5 lines

---
=C2=A0arch/powerpc/kernel/setup_64.c | 20 ++++++++++++++------ =C2=A01 file changed, 14 insertions(+), 6 deletions(-) =20
arch/powerpc/kernel/setup_6= renamed from arch/powerpc/kernel/setup_64.c +0 -0

4.c

Quoted 36 lines

index 7ac8e6e..ac75224 100644

arch/powerpc/kernel/setup_64.c +0 -0

@@ -226,17 +226,25 @@ static void __init configure_exceptions(void)
 =C2=A0		if (firmware_has_feature(FW_FEATURE_OPAL))
 =C2=A0			opal_configure_cores();

=C2=A0

arch/powerpc/kernel/setup_64.c +1 -6

-		/* Enable AIL if supported, and we are in hypervisor mode */
-		if (early_cpu_has_feature(CPU_FTR_HVMODE) &&
-		=C2=A0=C2=A0=C2=A0=C2=A0early_cpu_has_feature(CPU_FTR_ARCH_207S)) {
-			unsigned long lpcr =3D mfspr(SPRN_LPCR);
-			mtspr(SPRN_LPCR, lpcr | LPCR_AIL_3);
-		}
+		/* AIL on native is done in cpu_ready_for_interrupts */

=C2=A0 }
=C2=A0}
=C2=A0
=C2=A0static void cpu_ready_for_interrupts(void)
=C2=A0{

arch/powerpc/kernel/setup_64.c +13 -0

+	/*
+	=C2=A0* Enable AIL if supported, and we are in hypervisor mode. This
+	=C2=A0* is called once for every processor.
+	=C2=A0*
+	=C2=A0* If we are not in hypervisor mode the job is done once for
+	=C2=A0* the whole partition in configure_exceptions().
+	=C2=A0*/
+	if (early_cpu_has_feature(CPU_FTR_HVMODE) &&
+	=C2=A0=C2=A0=C2=A0=C2=A0early_cpu_has_feature(CPU_FTR_ARCH_207S)) {
+		unsigned long lpcr =3D mfspr(SPRN_LPCR);
+		mtspr(SPRN_LPCR, lpcr | LPCR_AIL_3);
+	}
+

=C2=A0 /* Set IR and DR in PACA MSR */
=C2=A0 get_paca()->kernel_msr =3D MSR_KERNEL;
=C2=A0}
=20