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powerpc/powernv: Enable HAIL (HV AIL) for ISA v3.1 processors

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commit 49c1d07fd0 upstream.

Starting with ISA v3.1, LPCR[AIL] no longer controls the interrupt
mode for HV=1 interrupts. Instead, a new LPCR[HAIL] bit is defined
which behaves like AIL=3 for HV interrupts when set.

Set HAIL on bare metal to give us mmu-on interrupts and improve
performance.

This also fixes an scv bug: we don't implement scv real mode (AIL=0)
vectors because they are at an inconvenient location, so we just
disable scv support when AIL can not be set. However powernv assumes
that LPCR[AIL] will enable AIL mode so it enables scv support despite
HV interrupts being AIL=0, which causes scv interrupts to go off into
the weeds.

Fixes: 7fa95f9ada ("powerpc/64s: system call support for scv/rfscv instructions")
Cc: stable@vger.kernel.org # v5.9+
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210402024124.545826-1-npiggin@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Nicholas Piggin 2021-04-02 12:41:24 +10:00 • committed by Greg Kroah-Hartman
commit 293c30ce25
2 changed files with 17 additions and 3 deletions
Download patch file Download diff file Expand all files Collapse all files

1
arch/powerpc/include/asm/reg.h
View file

@ -444,6 +444,7 @@
#define LPCR_VRMA_LP1 ASM_CONST(0x0000800000000000)
#define LPCR_RMLS 0x1C000000 /* Implementation dependent RMO limit sel */
#define LPCR_RMLS_SH 26
#define LPCR_HAIL ASM_CONST(0x0000000004000000) /* HV AIL (ISAv3.1) */
#define LPCR_ILE ASM_CONST(0x0000000002000000) /* !HV irqs set MSR:LE */
#define LPCR_AIL ASM_CONST(0x0000000001800000) /* Alternate interrupt location */
#define LPCR_AIL_0 ASM_CONST(0x0000000000000000) /* MMU off exception offset 0x0 */

19
arch/powerpc/kernel/setup_64.c
View file

@ -231,10 +231,23 @@ static void cpu_ready_for_interrupts(void)
* If we are not in hypervisor mode the job is done once for
* the whole partition in configure_exceptions().
*/
if (cpu_has_feature(CPU_FTR_HVMODE) &&
cpu_has_feature(CPU_FTR_ARCH_207S)) {
if (cpu_has_feature(CPU_FTR_HVMODE)) {
unsigned long lpcr = mfspr(SPRN_LPCR);
mtspr(SPRN_LPCR, lpcr | LPCR_AIL_3);
unsigned long new_lpcr = lpcr;
if (cpu_has_feature(CPU_FTR_ARCH_31)) {
/* P10 DD1 does not have HAIL */
if (pvr_version_is(PVR_POWER10) &&
(mfspr(SPRN_PVR) & 0xf00) == 0x100)
new_lpcr |= LPCR_AIL_3;
else
new_lpcr |= LPCR_HAIL;
} else if (cpu_has_feature(CPU_FTR_ARCH_207S)) {
new_lpcr |= LPCR_AIL_3;
}
if (new_lpcr != lpcr)
mtspr(SPRN_LPCR, new_lpcr);
}
/*