| Message ID | 1429610931-14903-1-git-send-email-ard.biesheuvel@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Apr 21, 2015 at 12:08:51PM +0200, Ard Biesheuvel wrote: > This updates the PROCINFO offset-to-setup-function fields of the > Thumb2 capable CPU definitions to include the Thumb bit when building > a Thumb2 kernel. This ensures that these function are always called > in the correct mode. I don't think this is necessary, in fact, I think this is positively regression causing. The symbol 'initfunc' is known to the assembler to be a thumb symbol. As we have seen already from the kernel dumps from the V7M kernel, when it calculates initfunc - name in a T2 kernel, the resulting value is an _odd_ number. Using BSYM() here will increment it to be the next _even_ number, which is wrong as this will potentially point at either half way through a 32-bit T2 instruction, or the second 16-bit T2 instruction.
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S index 3d1054f11a8a..eb3f66cb8ad0 100644 --- a/arch/arm/mm/proc-v7.S +++ b/arch/arm/mm/proc-v7.S @@ -492,7 +492,7 @@ __v7_setup_stack: PMD_SECT_AF | PMD_FLAGS_UP | \mm_mmuflags) .long PMD_TYPE_SECT | PMD_SECT_AP_WRITE | \ PMD_SECT_AP_READ | PMD_SECT_AF | \io_mmuflags - initfn \initfunc, \name + initfn BSYM(\initfunc), \name .long cpu_arch_name .long cpu_elf_name .long HWCAP_SWP | HWCAP_HALF | HWCAP_THUMB | HWCAP_FAST_MULT | \ diff --git a/arch/arm/mm/proc-v7m.S b/arch/arm/mm/proc-v7m.S index e08e1f2bab76..e85c3b98d4b6 100644 --- a/arch/arm/mm/proc-v7m.S +++ b/arch/arm/mm/proc-v7m.S @@ -146,7 +146,7 @@ __v7m_proc_info: .long 0x000f0000 @ Mask for ID .long 0 @ proc_info_list.__cpu_mm_mmu_flags .long 0 @ proc_info_list.__cpu_io_mmu_flags - initfn __v7m_setup, __v7m_proc_info @ proc_info_list.__cpu_flush + initfn BSYM(__v7m_setup), __v7m_proc_info @ proc_info_list.__cpu_flush .long cpu_arch_name .long cpu_elf_name .long HWCAP_HALF|HWCAP_THUMB|HWCAP_FAST_MULT
This updates the PROCINFO offset-to-setup-function fields of the Thumb2 capable CPU definitions to include the Thumb bit when building a Thumb2 kernel. This ensures that these function are always called in the correct mode. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> --- arch/arm/mm/proc-v7.S | 2 +- arch/arm/mm/proc-v7m.S | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)