The assembler really does not like us reassigning things to the same label:
<instantiation>:7:9: error: invalid reassignment of non-absolute variable 'fs_label' This happens across a bunch of platforms: https://github.com/ClangBuiltLinux/linux/issues/1043 https://github.com/ClangBuiltLinux/linux/issues/1008 https://github.com/ClangBuiltLinux/linux/issues/920 https://github.com/ClangBuiltLinux/linux/issues/1050 There is no hope of getting this fixed in LLVM, so if we want to build with LLVM_IAS, we need to hack around it ourselves. For us the big problem comes from this: \#define USE_FIXED_SECTION(sname) \ fs_label = start_##sname; \ fs_start = sname##_start; \ use_ftsec sname; \#define USE_TEXT_SECTION() fs_label = start_text; \ fs_start = text_start; \ .text and in particular fs_label. I have tried to work around it by not setting those 'variables', and requiring that users of the variables instead track for themselves what section they are in. This isn't amazing, by any stretch, but it gets us further in the compilation. I'm still stuck with the following from head_64.S: .balign 8 p_end: .8byte _end - copy_to_here 4: /* * Now copy the rest of the kernel up to _end, add * _end - copy_to_here to the copy limit and run again. */ addis r8,r26,(ABS_ADDR(p_end, text))@ha ld r8,(ABS_ADDR(p_end, text))@l(r8) add r5,r5,r8 5: bl copy_and_flush /* copy the rest */ 9: b start_here_multiplatform Clang does not like this code - in particular it complains about the addis, saying <unknown>:0: error: expected relocatable expression I don't know what's special about p_end, because just above we do an ABS_ADDR(4f, text) and that seems to work just fine. Signed-off-by: Daniel Axtens <d...@axtens.net> --- arch/powerpc/include/asm/head-64.h | 12 +++++------ arch/powerpc/kernel/exceptions-64s.S | 31 ++++++++++++++-------------- arch/powerpc/kernel/head_64.S | 16 +++++++------- 3 files changed, 29 insertions(+), 30 deletions(-) diff --git a/arch/powerpc/include/asm/head-64.h b/arch/powerpc/include/asm/head-64.h index 7d8ccab47e86..43849a777f91 100644 --- a/arch/powerpc/include/asm/head-64.h +++ b/arch/powerpc/include/asm/head-64.h @@ -98,13 +98,9 @@ linker_stub_catch: \ . = sname##_len; #define USE_FIXED_SECTION(sname) \ - fs_label = start_##sname; \ - fs_start = sname##_start; \ use_ftsec sname; #define USE_TEXT_SECTION() \ - fs_label = start_text; \ - fs_start = text_start; \ .text #define CLOSE_FIXED_SECTION(sname) \ @@ -161,13 +157,15 @@ end_##sname: * - ABS_ADDR is used to find the absolute address of any symbol, from within * a fixed section. */ -#define DEFINE_FIXED_SYMBOL(label) \ - label##_absolute = (label - fs_label + fs_start) +// define label as being _in_ sname +#define DEFINE_FIXED_SYMBOL(label, sname) \ + label##_absolute = (label - start_ ## sname + sname ## _start) #define FIXED_SYMBOL_ABS_ADDR(label) \ (label##_absolute) -#define ABS_ADDR(label) (label - fs_label + fs_start) +// find label from _within_ sname +#define ABS_ADDR(label, sname) (label - start_ ## sname + sname ## _start) #endif /* __ASSEMBLY__ */ diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index 720fb9892745..295d90202665 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -64,7 +64,7 @@ .balign IFETCH_ALIGN_BYTES; \ .global name; \ _ASM_NOKPROBE_SYMBOL(name); \ - DEFINE_FIXED_SYMBOL(name); \ + DEFINE_FIXED_SYMBOL(name, text); \ name: #define TRAMP_REAL_BEGIN(name) \ @@ -92,18 +92,18 @@ name: ld reg,PACAKBASE(r13); /* get high part of &label */ \ ori reg,reg,FIXED_SYMBOL_ABS_ADDR(label) -#define __LOAD_HANDLER(reg, label) \ +#define __LOAD_HANDLER(reg, label, section) \ ld reg,PACAKBASE(r13); \ - ori reg,reg,(ABS_ADDR(label))@l + ori reg,reg,(ABS_ADDR(label, section))@l /* * Branches from unrelocated code (e.g., interrupts) to labels outside * head-y require >64K offsets. */ -#define __LOAD_FAR_HANDLER(reg, label) \ +#define __LOAD_FAR_HANDLER(reg, label, section) \ ld reg,PACAKBASE(r13); \ - ori reg,reg,(ABS_ADDR(label))@l; \ - addis reg,reg,(ABS_ADDR(label))@h + ori reg,reg,(ABS_ADDR(label, section))@l; \ + addis reg,reg,(ABS_ADDR(label, section))@h /* * Branch to label using its 0xC000 address. This results in instruction @@ -113,8 +113,9 @@ name: * This could set the 0xc bits for !RELOCATABLE as an immediate, rather than * load KBASE for a slight optimisation. */ +// only called once #define BRANCH_TO_C000(reg, label) \ - __LOAD_FAR_HANDLER(reg, label); \ + __LOAD_FAR_HANDLER(reg, label, real_trampolines); \ mtctr reg; \ bctr @@ -458,7 +459,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_CFAR) * This switches to virtual mode and sets MSR[RI]. */ .macro __GEN_COMMON_ENTRY name -DEFINE_FIXED_SYMBOL(\name\()_common_real) +DEFINE_FIXED_SYMBOL(\name\()_common_real, text) \name\()_common_real: .if IKVM_REAL KVMTEST \name @@ -481,7 +482,7 @@ DEFINE_FIXED_SYMBOL(\name\()_common_real) .endif .balign IFETCH_ALIGN_BYTES -DEFINE_FIXED_SYMBOL(\name\()_common_virt) +DEFINE_FIXED_SYMBOL(\name\()_common_virt, text) \name\()_common_virt: .if IKVM_VIRT KVMTEST \name @@ -495,7 +496,7 @@ DEFINE_FIXED_SYMBOL(\name\()_common_virt) * want to run in real mode. */ .macro __GEN_REALMODE_COMMON_ENTRY name -DEFINE_FIXED_SYMBOL(\name\()_common_real) +DEFINE_FIXED_SYMBOL(\name\()_common_real, text) \name\()_common_real: .if IKVM_REAL KVMTEST \name @@ -856,12 +857,12 @@ EXC_VIRT_END(system_call_vectored, 0x3000, 0x1000) #ifdef CONFIG_RELOCATABLE TRAMP_VIRT_BEGIN(system_call_vectored_tramp) - __LOAD_HANDLER(r10, system_call_vectored_common) + __LOAD_HANDLER(r10, system_call_vectored_common, virt_trampolines) mtctr r10 bctr TRAMP_VIRT_BEGIN(system_call_vectored_sigill_tramp) - __LOAD_HANDLER(r10, system_call_vectored_sigill) + __LOAD_HANDLER(r10, system_call_vectored_sigill, virt_trampolines) mtctr r10 bctr #endif @@ -1968,14 +1969,14 @@ END_FTR_SECTION_IFSET(CPU_FTR_REAL_LE) HMT_MEDIUM .if ! \virt - __LOAD_HANDLER(r10, system_call_common_real) + __LOAD_HANDLER(r10, system_call_common_real, real_vectors) mtctr r10 bctr .else li r10,MSR_RI mtmsrd r10,1 /* Set RI (EE=0) */ #ifdef CONFIG_RELOCATABLE - __LOAD_HANDLER(r10, system_call_common) + __LOAD_HANDLER(r10, system_call_common, virt_vectors) mtctr r10 bctr #else @@ -3075,7 +3076,7 @@ USE_FIXED_SECTION(virt_trampolines) .align 7 .globl __end_interrupts __end_interrupts: -DEFINE_FIXED_SYMBOL(__end_interrupts) +DEFINE_FIXED_SYMBOL(__end_interrupts, virt_trampolines) #ifdef CONFIG_PPC_970_NAP /* diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S index ece7f97bafff..3a10e9f55baa 100644 --- a/arch/powerpc/kernel/head_64.S +++ b/arch/powerpc/kernel/head_64.S @@ -156,7 +156,7 @@ __secondary_hold: /* Tell the master cpu we're here */ /* Relocation is off & we are located at an address less */ /* than 0x100, so only need to grab low order offset. */ - std r24,(ABS_ADDR(__secondary_hold_acknowledge))(0) + std r24,(ABS_ADDR(__secondary_hold_acknowledge, first_256B))(0) sync li r26,0 @@ -164,7 +164,7 @@ __secondary_hold: tovirt(r26,r26) #endif /* All secondary cpus wait here until told to start. */ -100: ld r12,(ABS_ADDR(__secondary_hold_spinloop))(r26) +100: ld r12,(ABS_ADDR(__secondary_hold_spinloop, first_256B))(r26) cmpdi 0,r12,0 beq 100b @@ -646,15 +646,15 @@ __after_prom_start: 3: #endif /* # bytes of memory to copy */ - lis r5,(ABS_ADDR(copy_to_here))@ha - addi r5,r5,(ABS_ADDR(copy_to_here))@l + lis r5,(ABS_ADDR(copy_to_here, text))@ha + addi r5,r5,(ABS_ADDR(copy_to_here, text))@l bl copy_and_flush /* copy the first n bytes */ /* this includes the code being */ /* executed here. */ /* Jump to the copy of this code that we just made */ - addis r8,r3,(ABS_ADDR(4f))@ha - addi r12,r8,(ABS_ADDR(4f))@l + addis r8,r3,(ABS_ADDR(4f, text))@ha + addi r12,r8,(ABS_ADDR(4f, text))@l mtctr r12 bctr @@ -666,8 +666,8 @@ p_end: .8byte _end - copy_to_here * Now copy the rest of the kernel up to _end, add * _end - copy_to_here to the copy limit and run again. */ - addis r8,r26,(ABS_ADDR(p_end))@ha - ld r8,(ABS_ADDR(p_end))@l(r8) + addis r8,r26,(ABS_ADDR(p_end, text))@ha + ld r8,(ABS_ADDR(p_end, text))@l(r8) add r5,r5,r8 5: bl copy_and_flush /* copy the rest */ -- 2.27.0
