Re: [PATCH] powerpc: Make set_endian() return EINVAL when not supporting little endian
From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2021-08-26 03:42:47
Also in:
lkml
Christophe Leroy [off-list ref] writes:
There is no point in modifying MSR_LE bit on CPUs not supporting little endian.
Isn't that an ABI break? set_endian(PR_ENDIAN_BIG) should work on a big endian CPU, even if it does nothing useful. cheers
quoted hunk ↗ jump to hunk
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 185beb290580..b2b9919795a2 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c@@ -1995,6 +1995,10 @@ int set_endian(struct task_struct *tsk, unsigned int val) { struct pt_regs *regs = tsk->thread.regs; + if (!cpu_has_feature(CPU_FTR_PPC_LE) && + !cpu_has_feature(CPU_FTR_REAL_LE)) + return -EINVAL; + if ((val == PR_ENDIAN_LITTLE && !cpu_has_feature(CPU_FTR_REAL_LE)) || (val == PR_ENDIAN_PPC_LITTLE && !cpu_has_feature(CPU_FTR_PPC_LE))) return -EINVAL;-- 2.25.0