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Message-ID: <CAAV8rnLsnHAF3Dj8nWDtHEvmoz8arBQGw9FjQTAnAKXCjHCwhQ@mail.gmail.com> Date: Wed, 26 Sep 2012 16:15:20 +0800 From: Tao Guo <glorioustao@...il.com> To: Jan Beulich <JBeulich@...e.com> Cc: Ingo Molnar <mingo@...e.hu>, stable@...nel.org, linux-kernel@...r.kernel.org, hpa@...or.com Subject: Re: [PATCH] x86_64: Work around old gas bug On 9/26/12, Jan Beulich <JBeulich@...e.com> wrote: >>>> On 26.09.12 at 08:15, Tao Guo <glorioustao@...il.com> wrote: >> gas in binutils(2.16.91) could not parse parentheses within macro >> parameters, > > This description of yours contradicts the last hunk of the patch - > iirc the requirement for macro parameters in those old gas > versions is to be fully parenthesized if there's any blank inside > (which could possibly not even be present in source code, but > get inserted by the C preprocessor). Yes, the description is a little misleading and I have corrected in the new patch. > >> and this is a workaround to make old gas work without >> generating below errors: >> arch/x86/kernel/entry_64.S: Assembler messages: >> arch/x86/kernel/entry_64.S:387: Error: too many positional arguments >> arch/x86/kernel/entry_64.S:389: Error: too many positional arguments >> arch/x86/kernel/entry_64.S:390: Error: too many positional arguments >> arch/x86/kernel/entry_64.S:391: Error: too many positional arguments >> arch/x86/kernel/entry_64.S:392: Error: too many positional arguments >> arch/x86/kernel/entry_64.S:393: Error: too many positional arguments >> arch/x86/kernel/entry_64.S:394: Error: too many positional arguments >> >> Signed-off-by: Tao Guo <glorioustao@...il.com> >> --- >> arch/x86/include/asm/calling.h | 52 >> +++++++++++++++++++-------------------- >> arch/x86/kernel/entry_64.S | 18 +++++++------- >> 2 files changed, 34 insertions(+), 36 deletions(-) >> >> diff --git a/arch/x86/include/asm/calling.h >> b/arch/x86/include/asm/calling.h >> index a9e3a74..7627e26 100644 >> --- a/arch/x86/include/asm/calling.h >> +++ b/arch/x86/include/asm/calling.h >> @@ -49,38 +49,36 @@ For 32-bit we have the following conventions - kernel >> is >> built with >> #include "dwarf2.h" >> >> /* >> - * 64-bit system call stack frame layout defines and helpers, for >> - * assembly code (note that the seemingly unnecessary parentheses >> - * are to prevent cpp from inserting spaces in expressions that get >> - * passed to macros): >> + * 64-bit system call stack frame layout defines and helpers, >> + * for assembly code: >> */ >> >> -#define R15 (0) >> -#define R14 (8) >> -#define R13 (16) >> -#define R12 (24) >> -#define RBP (32) >> -#define RBX (40) >> +#define R15 0 >> +#define R14 8 >> +#define R13 16 >> +#define R12 24 >> +#define RBP 32 >> +#define RBX 40 >> >> /* arguments: interrupts/non tracing syscalls only save up to here: */ >> -#define R11 (48) >> -#define R10 (56) >> -#define R9 (64) >> -#define R8 (72) >> -#define RAX (80) >> -#define RCX (88) >> -#define RDX (96) >> -#define RSI (104) >> -#define RDI (112) >> -#define ORIG_RAX (120) /* + error_code */ >> +#define R11 48 >> +#define R10 56 >> +#define R9 64 >> +#define R8 72 >> +#define RAX 80 >> +#define RCX 88 >> +#define RDX 96 >> +#define RSI 104 >> +#define RDI 112 >> +#define ORIG_RAX 120 /* + error_code */ >> /* end of arguments */ >> >> /* cpu exception frame or undefined in case of fast syscall: */ >> -#define RIP (128) >> -#define CS (136) >> -#define EFLAGS (144) >> -#define RSP (152) >> -#define SS (160) >> +#define RIP 128 >> +#define CS 136 >> +#define EFLAGS 144 >> +#define RSP 152 >> +#define SS 160 >> >> #define ARGOFFSET R11 >> #define SWFRAME ORIG_RAX > > While up the here the changes are certainly acceptable, ... > >> @@ -107,7 +105,7 @@ For 32-bit we have the following conventions - kernel >> is >> built with >> >> .endm >> >> -#define ARG_SKIP (9*8) >> +#define ARG_SKIP 9*8 >> >> .macro RESTORE_ARGS rstor_rax=1, addskip=0, rstor_rcx=1, rstor_r11=1, \ >> rstor_r8910=1, rstor_rdx=1 >> @@ -157,7 +155,7 @@ For 32-bit we have the following conventions - kernel >> is >> built with >> .endif >> .endm >> >> -#define REST_SKIP (6*8) >> +#define REST_SKIP 6*8 >> >> .macro SAVE_REST >> subq $REST_SKIP, %rsp > > ... these two ones aren't - you can't simply remove parentheses > from expressions without causing (potentially future) problems, > up to and including someone re-introducing the parentheses to > address such problems. You ought to parenthesize the macro > parameters where needed instead, as you did below. Thanks for the suggestion and I will correct it in the new patch. > > But that's all leaving aside that in the past it was already > suggested (by hpa iirc) to simply declare these 2.16-based > assemblers non-suitable for building the kernel. Yes, that's another way to solve such compiling problems; People can at least get some instructions to solve their problems. Thanks, -Tao > > Jan > >> diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S >> index 69babd8..784a5b6 100644 >> --- a/arch/x86/kernel/entry_64.S >> +++ b/arch/x86/kernel/entry_64.S >> @@ -342,15 +342,15 @@ ENDPROC(native_usergs_sysret64) >> .macro SAVE_ARGS_IRQ >> cld >> /* start from rbp in pt_regs and jump over */ >> - movq_cfi rdi, RDI-RBP >> - movq_cfi rsi, RSI-RBP >> - movq_cfi rdx, RDX-RBP >> - movq_cfi rcx, RCX-RBP >> - movq_cfi rax, RAX-RBP >> - movq_cfi r8, R8-RBP >> - movq_cfi r9, R9-RBP >> - movq_cfi r10, R10-RBP >> - movq_cfi r11, R11-RBP >> + movq_cfi rdi, (RDI-RBP) >> + movq_cfi rsi, (RSI-RBP) >> + movq_cfi rdx, (RDX-RBP) >> + movq_cfi rcx, (RCX-RBP) >> + movq_cfi rax, (RAX-RBP) >> + movq_cfi r8, (R8-RBP) >> + movq_cfi r9, (R9-RBP) >> + movq_cfi r10, (R10-RBP) >> + movq_cfi r11, (R11-RBP) >> >> /* Save rbp so that we can unwind from get_irq_regs() */ >> movq_cfi rbp, 0 >> -- >> 1.7.7 > > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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