2023-08-03 19:27:16

by Nick Desaulniers

Subject: [PATCH v3] powerpc/inst: add PPC_TLBILX_LPID

Clang didn't recognize the instruction tlbilxlpid. This was fixed in
clang-18 [0] then backported to clang-17 [1]. To support clang-16 and
older, rather than using that instruction bare in inline asm, add it to
ppc-opcode.h and use that macro as is done elsewhere for other
instructions.

Link: https://github.com/ClangBuiltLinux/linux/issues/1891
Link: https://github.com/llvm/llvm-project/issues/64080
Link: https://github.com/llvm/llvm-project/commit/53648ac1d0c953ae6d008864dd2eddb437a92468 [0]
Link: https://github.com/llvm/llvm-project-release-prs/commit/0af7e5e54a8c7ac665773ac1ada328713e8338f5 [1]
Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/llvm/[email protected]/
Suggested-by: Michael Ellerman <[email protected]>
Signed-off-by: Nick Desaulniers <[email protected]>
---
Changes in v3:
- left comment @ https://github.com/linuxppc/issues/issues/350#issuecomment-1664417212
- restore PPC_RAW_TLBILX previous definition
- fix comment style
- Link to v2: https://lore.kernel.org/r/[email protected]

Changes in v2:
- add 2 missing tabs to PPC_RAW_TLBILX_LPID
- Link to v1: https://lore.kernel.org/r/[email protected]
---
arch/powerpc/include/asm/ppc-opcode.h | 2 ++
arch/powerpc/kvm/e500mc.c | 11 ++++++++---
2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/include/asm/ppc-opcode.h b/arch/powerpc/include/asm/ppc-opcode.h
index ef6972aa33b9..005601243dda 100644
--- a/arch/powerpc/include/asm/ppc-opcode.h
+++ b/arch/powerpc/include/asm/ppc-opcode.h
@@ -397,6 +397,7 @@
#define PPC_RAW_RFCI (0x4c000066)
#define PPC_RAW_RFDI (0x4c00004e)
#define PPC_RAW_RFMCI (0x4c00004c)
+#define PPC_RAW_TLBILX_LPID (0x7c000024)
#define PPC_RAW_TLBILX(t, a, b) (0x7c000024 | __PPC_T_TLB(t) | __PPC_RA0(a) | __PPC_RB(b))
#define PPC_RAW_WAIT_v203 (0x7c00007c)
#define PPC_RAW_WAIT(w, p) (0x7c00003c | __PPC_WC(w) | __PPC_PL(p))
@@ -616,6 +617,7 @@
#define PPC_TLBILX(t, a, b) stringify_in_c(.long PPC_RAW_TLBILX(t, a, b))
#define PPC_TLBILX_ALL(a, b) PPC_TLBILX(0, a, b)
#define PPC_TLBILX_PID(a, b) PPC_TLBILX(1, a, b)
+#define PPC_TLBILX_LPID stringify_in_c(.long PPC_RAW_TLBILX_LPID)
#define PPC_TLBILX_VA(a, b) PPC_TLBILX(3, a, b)
#define PPC_WAIT_v203 stringify_in_c(.long PPC_RAW_WAIT_v203)
#define PPC_WAIT(w, p) stringify_in_c(.long PPC_RAW_WAIT(w, p))
diff --git a/arch/powerpc/kvm/e500mc.c b/arch/powerpc/kvm/e500mc.c
index d58df71ace58..7c09c000c330 100644
--- a/arch/powerpc/kvm/e500mc.c
+++ b/arch/powerpc/kvm/e500mc.c
@@ -16,10 +16,11 @@
#include <linux/miscdevice.h>
#include <linux/module.h>

-#include <asm/reg.h>
#include <asm/cputable.h>
-#include <asm/kvm_ppc.h>
#include <asm/dbell.h>
+#include <asm/kvm_ppc.h>
+#include <asm/ppc-opcode.h>
+#include <asm/reg.h>

#include "booke.h"
#include "e500.h"
@@ -92,7 +93,11 @@ void kvmppc_e500_tlbil_all(struct kvmppc_vcpu_e500 *vcpu_e500)

local_irq_save(flags);
mtspr(SPRN_MAS5, MAS5_SGS | get_lpid(&vcpu_e500->vcpu));
- asm volatile("tlbilxlpid");
+ /*
+ * clang-17 and older could not assemble tlbilxlpid.
+ * https://github.com/ClangBuiltLinux/linux/issues/1891
+ */
+ asm volatile (PPC_TLBILX_LPID);
mtspr(SPRN_MAS5, 0);
local_irq_restore(flags);
}

---
base-commit: 7bafbd4027ae86572f308c4ddf93120c90126332
change-id: 20230803-ppc_tlbilxlpid-cfdbf4fd4f7f

Best regards,
--
Nick Desaulniers <[email protected]>

2023-08-23 20:38:24

by Michael Ellerman

Subject: Re: [PATCH v3] powerpc/inst: add PPC_TLBILX_LPID

On Thu, 03 Aug 2023 11:33:52 -0700, Nick Desaulniers wrote:
> Clang didn't recognize the instruction tlbilxlpid. This was fixed in
> clang-18 [0] then backported to clang-17 [1]. To support clang-16 and
> older, rather than using that instruction bare in inline asm, add it to
> ppc-opcode.h and use that macro as is done elsewhere for other
> instructions.
>
>
> [...]

Applied to powerpc/next.

[1/1] powerpc/inst: add PPC_TLBILX_LPID
https://git.kernel.org/powerpc/c/ae7936d232d862e5b8311180036281ffe93735b8

cheers