From: Nathan Chancellor <nathan@kernel.org> To: Paul Walmsley <paul.walmsley@sifive.com>, Palmer Dabbelt <palmer@dabbelt.com>, Albert Ou <aou@eecs.berkeley.edu> Cc: Nick Desaulniers <ndesaulniers@google.com>, Heiko Stuebner <heiko@sntech.de>, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, patches@lists.linux.dev, Nathan Chancellor <nathan@kernel.org>, Jessica Clarke <jrtc27@jrtc27.com> Subject: [PATCH] riscv: Fix ALT_THEAD_PMA's asm parameters Date: Wed, 18 May 2022 11:45:29 -0700 [thread overview] Message-ID: <20220518184529.454008-1-nathan@kernel.org> (raw) After commit a35707c3d850 ("riscv: add memory-type errata for T-Head"), builds with LLVM's integrated assembler fail like: In file included from arch/riscv/kernel/asm-offsets.c:10: In file included from ./include/linux/mm.h:29: In file included from ./include/linux/pgtable.h:6: In file included from ./arch/riscv/include/asm/pgtable.h:114: ./arch/riscv/include/asm/pgtable-64.h:210:2: error: invalid input constraint '0' in asm ALT_THEAD_PMA(prot_val); ^ ./arch/riscv/include/asm/errata_list.h:88:4: note: expanded from macro 'ALT_THEAD_PMA' : "0"(_val), \ ^ This was reported upstream to LLVM where Jessica pointed out a couple of issues with the existing implementation of ALT_THEAD_PMA: * t3 is modified but not listed in the clobbers list. * "+r"(_val) marks _val as both an input and output of the asm but then "0"(_val) marks _val as an input matching constraint, which does not make much sense in this situation, as %1 is not actually used in the asm and matching constraints are designed to be used for different inputs that need to use the same register. Drop the matching contraint and shift all the operands by one, as %1 is unused, and mark t3 as clobbered. This resolves the build error and goes not cause any problems with GNU as. Fixes: a35707c3d850 ("riscv: add memory-type errata for T-Head") Link: https://github.com/ClangBuiltLinux/linux/issues/1641 Link: https://github.com/llvm/llvm-project/issues/55514 Link: https://gcc.gnu.org/onlinedocs/gcc/Simple-Constraints.html Suggested-by: Jessica Clarke <jrtc27@jrtc27.com> Signed-off-by: Nathan Chancellor <nathan@kernel.org> --- arch/riscv/include/asm/errata_list.h | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/arch/riscv/include/asm/errata_list.h b/arch/riscv/include/asm/errata_list.h index 9e2888dbb5b1..416ead0f9a65 100644 --- a/arch/riscv/include/asm/errata_list.h +++ b/arch/riscv/include/asm/errata_list.h @@ -75,20 +75,20 @@ asm volatile(ALTERNATIVE( \ "nop\n\t" \ "nop\n\t" \ "nop", \ - "li t3, %2\n\t" \ - "slli t3, t3, %4\n\t" \ + "li t3, %1\n\t" \ + "slli t3, t3, %3\n\t" \ "and t3, %0, t3\n\t" \ "bne t3, zero, 2f\n\t" \ - "li t3, %3\n\t" \ - "slli t3, t3, %4\n\t" \ + "li t3, %2\n\t" \ + "slli t3, t3, %3\n\t" \ "or %0, %0, t3\n\t" \ "2:", THEAD_VENDOR_ID, \ ERRATA_THEAD_PBMT, CONFIG_ERRATA_THEAD_PBMT) \ : "+r"(_val) \ - : "0"(_val), \ - "I"(_PAGE_MTMASK_THEAD >> ALT_THEAD_PBMT_SHIFT), \ + : "I"(_PAGE_MTMASK_THEAD >> ALT_THEAD_PBMT_SHIFT), \ "I"(_PAGE_PMA_THEAD >> ALT_THEAD_PBMT_SHIFT), \ - "I"(ALT_THEAD_PBMT_SHIFT)) + "I"(ALT_THEAD_PBMT_SHIFT) \ + : "t3") #else #define ALT_THEAD_PMA(_val) #endif base-commit: 93c0651617a62a69717299f1464dda798af8bebb -- 2.36.1
WARNING: multiple messages have this Message-ID (diff)
From: Nathan Chancellor <nathan@kernel.org> To: Paul Walmsley <paul.walmsley@sifive.com>, Palmer Dabbelt <palmer@dabbelt.com>, Albert Ou <aou@eecs.berkeley.edu> Cc: Nick Desaulniers <ndesaulniers@google.com>, Heiko Stuebner <heiko@sntech.de>, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, patches@lists.linux.dev, Nathan Chancellor <nathan@kernel.org>, Jessica Clarke <jrtc27@jrtc27.com> Subject: [PATCH] riscv: Fix ALT_THEAD_PMA's asm parameters Date: Wed, 18 May 2022 11:45:29 -0700 [thread overview] Message-ID: <20220518184529.454008-1-nathan@kernel.org> (raw) After commit a35707c3d850 ("riscv: add memory-type errata for T-Head"), builds with LLVM's integrated assembler fail like: In file included from arch/riscv/kernel/asm-offsets.c:10: In file included from ./include/linux/mm.h:29: In file included from ./include/linux/pgtable.h:6: In file included from ./arch/riscv/include/asm/pgtable.h:114: ./arch/riscv/include/asm/pgtable-64.h:210:2: error: invalid input constraint '0' in asm ALT_THEAD_PMA(prot_val); ^ ./arch/riscv/include/asm/errata_list.h:88:4: note: expanded from macro 'ALT_THEAD_PMA' : "0"(_val), \ ^ This was reported upstream to LLVM where Jessica pointed out a couple of issues with the existing implementation of ALT_THEAD_PMA: * t3 is modified but not listed in the clobbers list. * "+r"(_val) marks _val as both an input and output of the asm but then "0"(_val) marks _val as an input matching constraint, which does not make much sense in this situation, as %1 is not actually used in the asm and matching constraints are designed to be used for different inputs that need to use the same register. Drop the matching contraint and shift all the operands by one, as %1 is unused, and mark t3 as clobbered. This resolves the build error and goes not cause any problems with GNU as. Fixes: a35707c3d850 ("riscv: add memory-type errata for T-Head") Link: https://github.com/ClangBuiltLinux/linux/issues/1641 Link: https://github.com/llvm/llvm-project/issues/55514 Link: https://gcc.gnu.org/onlinedocs/gcc/Simple-Constraints.html Suggested-by: Jessica Clarke <jrtc27@jrtc27.com> Signed-off-by: Nathan Chancellor <nathan@kernel.org> --- arch/riscv/include/asm/errata_list.h | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/arch/riscv/include/asm/errata_list.h b/arch/riscv/include/asm/errata_list.h index 9e2888dbb5b1..416ead0f9a65 100644 --- a/arch/riscv/include/asm/errata_list.h +++ b/arch/riscv/include/asm/errata_list.h @@ -75,20 +75,20 @@ asm volatile(ALTERNATIVE( \ "nop\n\t" \ "nop\n\t" \ "nop", \ - "li t3, %2\n\t" \ - "slli t3, t3, %4\n\t" \ + "li t3, %1\n\t" \ + "slli t3, t3, %3\n\t" \ "and t3, %0, t3\n\t" \ "bne t3, zero, 2f\n\t" \ - "li t3, %3\n\t" \ - "slli t3, t3, %4\n\t" \ + "li t3, %2\n\t" \ + "slli t3, t3, %3\n\t" \ "or %0, %0, t3\n\t" \ "2:", THEAD_VENDOR_ID, \ ERRATA_THEAD_PBMT, CONFIG_ERRATA_THEAD_PBMT) \ : "+r"(_val) \ - : "0"(_val), \ - "I"(_PAGE_MTMASK_THEAD >> ALT_THEAD_PBMT_SHIFT), \ + : "I"(_PAGE_MTMASK_THEAD >> ALT_THEAD_PBMT_SHIFT), \ "I"(_PAGE_PMA_THEAD >> ALT_THEAD_PBMT_SHIFT), \ - "I"(ALT_THEAD_PBMT_SHIFT)) + "I"(ALT_THEAD_PBMT_SHIFT) \ + : "t3") #else #define ALT_THEAD_PMA(_val) #endif base-commit: 93c0651617a62a69717299f1464dda798af8bebb -- 2.36.1 _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv
next reply other threads:[~2022-05-18 18:45 UTC|newest] Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-05-18 18:45 Nathan Chancellor [this message] 2022-05-18 18:45 ` [PATCH] riscv: Fix ALT_THEAD_PMA's asm parameters Nathan Chancellor 2022-05-18 20:45 ` Nick Desaulniers 2022-05-18 20:45 ` Nick Desaulniers 2022-05-19 7:21 ` Heiko Stübner 2022-05-19 7:21 ` Heiko Stübner 2022-05-26 2:40 ` Nathan Chancellor 2022-05-26 2:40 ` Nathan Chancellor 2022-06-13 20:26 ` Nathan Chancellor 2022-06-13 20:26 ` Nathan Chancellor 2022-06-17 21:54 ` Palmer Dabbelt 2022-06-17 21:54 ` Palmer Dabbelt 2022-06-17 21:57 ` Nathan Chancellor 2022-06-17 21:57 ` Nathan Chancellor
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