Re: [PATCH v2] powerpc/mm: Fix missing KUAP disable in flush_coherent_icache()

[Andrew Donnellan]

On 4/3/20 10:57 am, Michael Ellerman wrote:

diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index ef7b1119b2e2..36a8c7b105ce 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -373,7 +373,9 @@ static inline bool flush_coherent_icache(unsigned long addr)
         */
        if (cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) {
                mb(); /* sync */
+               allow_read_from_user((void *)addr, L1_CACHE_BYTES);
                icbi((void *)addr);
+               prevent_read_from_user((void *)addr, L1_CACHE_BYTES);
                mb(); /* sync */
                isync();
                return true;

(void *) should be (const void __user *) to avoid sparse warnings.

snowpatch reports: https://patchwork.ozlabs.org/patch/1248671/

--
Andrew Donnellan              OzLabs, ADL Canberra
a...@linux.ibm.com             IBM Australia Limited