| Message ID | 20190716194829.15483-1-desnesn@linux.ibm.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | powerpc/64: mark __boot_from_prom and start_here_common as __ref | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch next (f5c20693d8edcd665f1159dc941b9e7f87c17647) |
| snowpatch_ozlabs/build-ppc64le | success | Build succeeded |
| snowpatch_ozlabs/build-ppc64be | success | Build succeeded |
| snowpatch_ozlabs/build-ppc64e | success | Build succeeded |
| snowpatch_ozlabs/build-pmac32 | success | Build succeeded |
| snowpatch_ozlabs/checkpatch | warning | total: 0 errors, 1 warnings, 0 checks, 28 lines checked |
diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S index 259be7f6d551..04b34397b656 100644 --- a/arch/powerpc/kernel/head_64.S +++ b/arch/powerpc/kernel/head_64.S @@ -540,6 +540,7 @@ __start_initialization_multiplatform: b __after_prom_start #endif /* CONFIG_PPC_BOOK3E */ +__REF __boot_from_prom: #ifdef CONFIG_PPC_OF_BOOT_TRAMPOLINE /* Save parameters */ @@ -577,6 +578,7 @@ __boot_from_prom: /* We never return. We also hit that trap if trying to boot * from OF while CONFIG_PPC_OF_BOOT_TRAMPOLINE isn't selected */ trap + .previous __after_prom_start: #ifdef CONFIG_RELOCATABLE @@ -983,6 +985,7 @@ start_here_multiplatform: .previous /* This is where all platforms converge execution */ +__REF start_here_common: /* relocation is on at this point */ std r1,PACAKSAVE(r13) @@ -1003,6 +1006,7 @@ start_here_common: /* Not reached */ BUG_OPCODE + .previous /* * We put a few things here that have to be page-aligned.
Functions `__boot_from_prom` and `start_here_common` are "init code" in the sense that they are only executed at boot time, nevertheless they should not be tagged as __init since this will carry them to a different section located at the very end of kernel text. If the TOC is not set up, the kernel may not be able to tolerate a branch trampoline to reach the init function. Thus, these functions should be marked as `__ref` and the assembler must be reminded to insert the code that follows into the last active section by the use of the `.previous` directive. This will allow the powerpc kernel to be built with CONFIG_SECTION_MISMATCH_WARN_ONLY disabled and quieten the following modpost warnings during compilation: WARNING: vmlinux.o(.text+0x2ad4): Section mismatch in reference from the variable __boot_from_prom to the function .init.text:prom_init() The function __boot_from_prom() references the function __init prom_init(). This is often because __boot_from_prom lacks a __init annotation or the annotation of prom_init is wrong. WARNING: vmlinux.o(.text+0x2cd0): Section mismatch in reference from the variable start_here_common to the function .init.text:start_kernel() The function start_here_common() references the function __init start_kernel(). This is often because start_here_common lacks a __init annotation or the annotation of start_kernel is wrong. Credits: code is based on commit <9c4e4c90ec24> ("powerpc/64: mark start_here_multiplatform as __ref") and message is based on 2016 patch by Nicholas Piggin: https://lore.kernel.org/linuxppc-dev/20161222131419.18062-1-npiggin@gmail.com/ Signed-off-by: Desnes A. Nunes do Rosario <desnesn@linux.ibm.com> --- arch/powerpc/kernel/head_64.S | 4 ++++ 1 file changed, 4 insertions(+)