Commit ee263160 authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

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: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/2414d662558e7fb27d1ed41c8e47c591d576acac.1634627931.git.christophe.leroy@csgroup.eu
parent 13dac4e3

arch/powerpc/include/asm/nohash/32/mmu-44x.h

+0 −1
Original line number Diff line number Diff line
@@ -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__ */

arch/powerpc/kernel/head_44x.S

+2 −8
Original line number Diff line number Diff line
@@ -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.

arch/powerpc/mm/nohash/44x.c

+1 −7
Original line number Diff line number Diff line
@@ -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()));

}

#endif

arch/powerpc/platforms/Kconfig.cputype

+1 −0
Original line number Diff line number Diff line
@@ -63,6 +63,7 @@ config 44x 
	select HAVE_PCI

	select PHYS_64BIT

	select PPC_HAVE_KUEP

	select PPC_KUEP



endchoice