Commit 2a0fb3c1 authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc/32: Set an IBAT covering up to _einittext during init 



Always set an IBAT covering up to _einittext during init because when
CONFIG_MODULES is not selected there is no reason to have an exception
handler for kernel instruction TLB misses.

It implies DBAT and IBAT are now totaly independent, IBATs are set
by setibat() and DBAT by setbat().

This allows to revert commit 9bb162fa ("powerpc/603: Fix
boot failure with DEBUG_PAGEALLOC and KFENCE")

Reported-by: default avatarMaxime Bizon <mbizon@freebox.fr>
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/ce7f04a39593934d9b1ee68c69144ccd3d4da4a1.1655202804.git.christophe.leroy@csgroup.eu
parent 980bbf7c

arch/powerpc/kernel/head_book3s_32.S

+2 −2
Original line number Diff line number Diff line
@@ -418,14 +418,14 @@ InstructionTLBMiss: 
 */

	/* Get PTE (linux-style) and check access */

	mfspr	r3,SPRN_IMISS

#if defined(CONFIG_MODULES) || defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KFENCE)

#ifdef CONFIG_MODULES

	lis	r1, TASK_SIZE@h		/* check if kernel address */

	cmplw	0,r1,r3

#endif

	mfspr	r2, SPRN_SDR1

	li	r1,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC | _PAGE_USER

	rlwinm	r2, r2, 28, 0xfffff000

#if defined(CONFIG_MODULES) || defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KFENCE)

#ifdef CONFIG_MODULES

	bgt-	112f

	lis	r2, (swapper_pg_dir - PAGE_OFFSET)@ha	/* if kernel address, use */

	li	r1,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC

arch/powerpc/mm/book3s32/mmu.c

+4 −6
Original line number Diff line number Diff line
@@ -159,7 +159,10 @@ unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top) 
{

	unsigned long done;

	unsigned long border = (unsigned long)__init_begin - PAGE_OFFSET;

	unsigned long size;



	size = roundup_pow_of_two((unsigned long)_einittext - PAGE_OFFSET);

	setibat(0, PAGE_OFFSET, 0, size, PAGE_KERNEL_X);



	if (debug_pagealloc_enabled_or_kfence()) {

		pr_debug_once("Read-Write memory mapped without BATs\n");
@@ -245,10 +248,9 @@ void mmu_mark_rodata_ro(void) 
}



/*

 * Set up one of the I/D BAT (block address translation) register pairs.

 * Set up one of the D BAT (block address translation) register pairs.

 * The parameters are not checked; in particular size must be a power

 * of 2 between 128k and 256M.

 * On 603+, only set IBAT when _PAGE_EXEC is set

 */

void __init setbat(int index, unsigned long virt, phys_addr_t phys,

		   unsigned int size, pgprot_t prot)
@@ -284,10 +286,6 @@ void __init setbat(int index, unsigned long virt, phys_addr_t phys, 
		/* G bit must be zero in IBATs */

		flags &= ~_PAGE_EXEC;

	}

	if (flags & _PAGE_EXEC)

		bat[0] = bat[1];

	else

		bat[0].batu = bat[0].batl = 0;



	bat_addrs[index].start = virt;

	bat_addrs[index].limit = virt + ((bl + 1) << 17) - 1;