Re: [PATCH 4/9] MIPS: MT: Remove "weak" from vpe_run() declaration

From: James Hogan
Date: Mon Jul 13 2015 - 06:27:57 EST


On 13/07/15 00:11, Bjorn Helgaas wrote:
> Weak header file declarations are error-prone because they make every
> definition weak, and the linker chooses one based on link order (see
> 10629d711ed7 ("PCI: Remove __weak annotation from pcibios_get_phb_of_node
> decl")).
>
> That's not a problem for vpe_run() because Kconfig ensures there's never
> more than one definition:
>
> - vpe_run() is defined in arch/mips/kernel/vpe-mt.c if
> CONFIG_MIPS_VPE_LOADER_MT=y
>
> - vpe_run() is defined in arch/mips/mti-malta/malta-amon.c if
> CONFIG_MIPS_CMP=y
>
> - CONFIG_MIPS_VPE_LOADER_MT cannot be set if CONFIG_MIPS_CMP=y
>
> But it's simpler to verify correctness if we remove "weak" from the picture
> and test the config symbols directly.
>
> Remove "weak" from the vpe_run() declaration and use #if to test whether a
> definition should be present.
>
> Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> ---
> arch/mips/include/asm/vpe.h | 2 +-
> arch/mips/kernel/vpe.c | 10 +++++-----
> 2 files changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/arch/mips/include/asm/vpe.h b/arch/mips/include/asm/vpe.h
> index 7849f39..80e70db 100644
> --- a/arch/mips/include/asm/vpe.h
> +++ b/arch/mips/include/asm/vpe.h
> @@ -122,7 +122,7 @@ void release_vpe(struct vpe *v);
> void *alloc_progmem(unsigned long len);
> void release_progmem(void *ptr);
>
> -int __weak vpe_run(struct vpe *v);
> +int vpe_run(struct vpe *v);
> void cleanup_tc(struct tc *tc);
>
> int __init vpe_module_init(void);
> diff --git a/arch/mips/kernel/vpe.c b/arch/mips/kernel/vpe.c
> index 72cae9f..04539d6 100644
> --- a/arch/mips/kernel/vpe.c
> +++ b/arch/mips/kernel/vpe.c
> @@ -817,15 +817,11 @@ static int vpe_open(struct inode *inode, struct file *filp)
>
> static int vpe_release(struct inode *inode, struct file *filp)
> {
> +#if defined(CONFIG_MIPS_VPE_LOADER_MT) || defined(CONFIG_MIPS_CMP)

That should be CONFIG_MIPS_VPE_LOADER_CMP, in which case the error case
in the #else bit is always dead code. This file is built only if
CONFIG_MIPS_VPE_LOADER, and the other ones are defined without prompts:

config MIPS_VPE_LOADER_CMP
bool
default "y"
depends on MIPS_VPE_LOADER && MIPS_CMP

config MIPS_VPE_LOADER_MT
bool
default "y"
depends on MIPS_VPE_LOADER && !MIPS_CMP

I.e. one xor the other must be "y" when MIPS_VPE_LOADER=y.

Maybe its worth just removing the weak and the vpe_run check?

Cheers
James

> struct vpe *v;
> Elf_Ehdr *hdr;
> int ret = 0;
>
> - if (!vpe_run) {
> - pr_warn("VPE loader: ELF load failed.\n");
> - return -ENOEXEC;
> - }
> -
> v = get_vpe(aprp_cpu_index());
> if (v == NULL)
> return -ENODEV;
> @@ -855,6 +851,10 @@ static int vpe_release(struct inode *inode, struct file *filp)
> v->plen = 0;
>
> return ret;
> +#else
> + pr_warn("VPE loader: ELF load failed.\n");
> + return -ENOEXEC;
> +#endif
> }
>
> static ssize_t vpe_write(struct file *file, const char __user *buffer,
>

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