powerpc/44x: Activate KUEP at all time

On 44x, KUEP is implemented by clearing SX bit during TLB miss
for user pages. The impact is minimal and not worth neither
boot time nor build time selection.

Activate it at all time.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/2414d662558e7fb27d1ed41c8e47c591d576acac.1634627931.git.christophe.leroy@csgroup.eu

diff --git a/arch/powerpc/include/asm/nohash/32/mmu-44x.h b/arch/powerpc/include/asm/nohash/32/mmu-44x.h
index 43ceca1..2d92a39 100644 (file)
--- a/arch/powerpc/include/asm/nohash/32/mmu-44x.h
+++ b/arch/powerpc/include/asm/nohash/32/mmu-44x.h
@@ -113,7 +113,6 @@ typedef struct {
 
 /* patch sites */
 extern s32 patch__tlb_44x_hwater_D, patch__tlb_44x_hwater_I;
-extern s32 patch__tlb_44x_kuep, patch__tlb_47x_kuep;
 
 #endif /* !__ASSEMBLY__ */
 

diff --git a/arch/powerpc/kernel/head_44x.S b/arch/powerpc/kernel/head_44x.S
index 02d2928..916f7e9 100644 (file)
--- a/arch/powerpc/kernel/head_44x.S
+++ b/arch/powerpc/kernel/head_44x.S
@@ -532,10 +532,7 @@ finish_tlb_load_44x:
        andi.   r10,r12,_PAGE_USER              /* User page ? */
        beq     1f                              /* nope, leave U bits empty */
        rlwimi  r11,r11,3,26,28                 /* yes, copy S bits to U */
-#ifdef CONFIG_PPC_KUEP
-0:     rlwinm  r11,r11,0,~PPC44x_TLB_SX        /* Clear SX if User page */
-       patch_site 0b, patch__tlb_44x_kuep
-#endif
+       rlwinm  r11,r11,0,~PPC44x_TLB_SX        /* Clear SX if User page */
 1:     tlbwe   r11,r13,PPC44x_TLB_ATTRIB       /* Write ATTRIB */
 
        /* Done...restore registers and get out of here.
@@ -747,10 +744,7 @@ finish_tlb_load_47x:
        andi.   r10,r12,_PAGE_USER              /* User page ? */
        beq     1f                              /* nope, leave U bits empty */
        rlwimi  r11,r11,3,26,28                 /* yes, copy S bits to U */
-#ifdef CONFIG_PPC_KUEP
-0:     rlwinm  r11,r11,0,~PPC47x_TLB2_SX       /* Clear SX if User page */
-       patch_site 0b, patch__tlb_47x_kuep
-#endif
+       rlwinm  r11,r11,0,~PPC47x_TLB2_SX       /* Clear SX if User page */
 1:     tlbwe   r11,r13,2
 
        /* Done...restore registers and get out of here.

diff --git a/arch/powerpc/mm/nohash/44x.c b/arch/powerpc/mm/nohash/44x.c
index e079f26..ceb290d 100644 (file)
--- a/arch/powerpc/mm/nohash/44x.c
+++ b/arch/powerpc/mm/nohash/44x.c
@@ -247,12 +247,6 @@ void setup_kuep(bool disabled)
        if (smp_processor_id() != boot_cpuid)
                return;
 
-       if (disabled)
-               patch_instruction_site(&patch__tlb_44x_kuep, ppc_inst(PPC_RAW_NOP()));
-       else
-               pr_info("Activating Kernel Userspace Execution Prevention\n");
-
-       if (IS_ENABLED(CONFIG_PPC_47x) && disabled)
-               patch_instruction_site(&patch__tlb_47x_kuep, ppc_inst(PPC_RAW_NOP()));
+       pr_info("Activating Kernel Userspace Execution Prevention\n");
 }
 #endif

diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
index 8b36608..4f8774d 100644 (file)
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype
@@ -63,6 +63,7 @@ config 44x
        select HAVE_PCI
        select PHYS_64BIT
        select PPC_HAVE_KUEP
+       select PPC_KUEP
 
 endchoice