Re: [PATCH v3 04/12] powerpc: Prepare func_desc_t for refactorisation
From: Kees Cook <hidden>
Date: 2022-02-11 00:54:57
Also in:
linux-arch, linux-mm, lkml
On Sun, Oct 17, 2021 at 02:38:17PM +0200, Christophe Leroy wrote:
quoted hunk ↗ jump to hunk
In preparation of making func_desc_t generic, change the ELFv2 version to a struct containing 'addr' element. This allows using single helpers common to ELFv1 and ELFv2. Signed-off-by: Christophe Leroy <redacted> --- arch/powerpc/kernel/module_64.c | 32 ++++++++++++++------------------ 1 file changed, 14 insertions(+), 18 deletions(-)diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c index a89da0ee25e2..b687ef88c4c4 100644 --- a/arch/powerpc/kernel/module_64.c +++ b/arch/powerpc/kernel/module_64.c@@ -33,19 +33,13 @@ #ifdef PPC64_ELF_ABI_v2 /* An address is simply the address of the function. */ -typedef unsigned long func_desc_t; +typedef struct { + unsigned long addr; +} func_desc_t; static func_desc_t func_desc(unsigned long addr) { - return addr; -} -static unsigned long func_addr(unsigned long addr) -{ - return addr; -} -static unsigned long stub_func_addr(func_desc_t func) -{ - return func; + return (func_desc_t){addr};
There's only 1 element in the struct, so okay, but it hurt my eyes a
little. I would have been happier with:
return (func_desc_t){ .addr = addr; };
But of course that also looks bonkers because it starts with "return".
So no matter what I do my eyes bug out. ;)
So it's fine either way. :)
Reviewed-by: Kees Cook <redacted>
quoted hunk ↗ jump to hunk
} /* PowerPC64 specific values for the Elf64_Sym st_other field. */@@ -70,14 +64,6 @@ static func_desc_t func_desc(unsigned long addr) { return *(struct func_desc *)addr; } -static unsigned long func_addr(unsigned long addr) -{ - return func_desc(addr).addr; -} -static unsigned long stub_func_addr(func_desc_t func) -{ - return func.addr; -} static unsigned int local_entry_offset(const Elf64_Sym *sym) { return 0;@@ -93,6 +79,16 @@ void *dereference_module_function_descriptor(struct module *mod, void *ptr) } #endif +static unsigned long func_addr(unsigned long addr) +{ + return func_desc(addr).addr; +} + +static unsigned long stub_func_addr(func_desc_t func) +{ + return func.addr; +} + #define STUB_MAGIC 0x73747562 /* stub */ /* Like PPC32, we need little trampolines to do > 24-bit jumps (into-- 2.31.1
-- Kees Cook