From d4a06c59dfeb4012c13a113a450de5cc07dbad36 Mon Sep 17 00:00:00 2001 From: Jianguo Wu Date: Thu, 24 Apr 2014 03:45:56 +0100 Subject: [PATCH] ARM: 8037/1: mm: support big-endian page tables commit 86f40622af7329375e38f282f6c0aab95f3e5f72 upstream. When enable LPAE and big-endian in a hisilicon board, while specify mem=384M mem=512M@7680M, will get bad page state: Freeing unused kernel memory: 180K (c0466000 - c0493000) BUG: Bad page state in process init pfn:fa442 page:c7749840 count:0 mapcount:-1 mapping: (null) index:0x0 page flags: 0x40000400(reserved) Modules linked in: CPU: 0 PID: 1 Comm: init Not tainted 3.10.27+ #66 [] (unwind_backtrace+0x0/0x11c) from [] (show_stack+0x10/0x14) [] (show_stack+0x10/0x14) from [] (bad_page+0xd4/0x104) [] (bad_page+0xd4/0x104) from [] (free_pages_prepare+0xa8/0x14c) [] (free_pages_prepare+0xa8/0x14c) from [] (free_hot_cold_page+0x18/0xf0) [] (free_hot_cold_page+0x18/0xf0) from [] (handle_pte_fault+0xcf4/0xdc8) [] (handle_pte_fault+0xcf4/0xdc8) from [] (handle_mm_fault+0xf4/0x120) [] (handle_mm_fault+0xf4/0x120) from [] (do_page_fault+0xfc/0x354) [] (do_page_fault+0xfc/0x354) from [] (do_DataAbort+0x2c/0x90) [] (do_DataAbort+0x2c/0x90) from [] (__dabt_usr+0x34/0x40) The bad pfn:fa442 is not system memory(mem=384M mem=512M@7680M), after debugging, I find in page fault handler, will get wrong pfn from pte just after set pte, as follow: do_anonymous_page() { ... set_pte_at(mm, address, page_table, entry); //debug code pfn = pte_pfn(entry); pr_info("pfn:0x%lx, pte:0x%llxn", pfn, pte_val(entry)); //read out the pte just set new_pte = pte_offset_map(pmd, address); new_pfn = pte_pfn(*new_pte); pr_info("new pfn:0x%lx, new pte:0x%llxn", pfn, pte_val(entry)); ... } pfn: 0x1fa4f5, pte:0xc00001fa4f575f new_pfn:0xfa4f5, new_pte:0xc00000fa4f5f5f //new pfn/pte is wrong. The bug is happened in cpu_v7_set_pte_ext(ptep, pte): An LPAE PTE is a 64bit quantity, passed to cpu_v7_set_pte_ext in the r2 and r3 registers. On an LE kernel, r2 contains the LSB of the PTE, and r3 the MSB. On a BE kernel, the assignment is reversed. Unfortunately, the current code always assumes the LE case, leading to corruption of the PTE when clearing/setting bits. This patch fixes this issue much like it has been done already in the cpu_v7_switch_mm case. Signed-off-by: Jianguo Wu Acked-by: Marc Zyngier Acked-by: Will Deacon Signed-off-by: Russell King Signed-off-by: Greg Kroah-Hartman --- arch/arm/mm/proc-v7-3level.S | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/arch/arm/mm/proc-v7-3level.S b/arch/arm/mm/proc-v7-3level.S index 01a719e18bb047..22e3ad63500c0e 100644 --- a/arch/arm/mm/proc-v7-3level.S +++ b/arch/arm/mm/proc-v7-3level.S @@ -64,6 +64,14 @@ ENTRY(cpu_v7_switch_mm) mov pc, lr ENDPROC(cpu_v7_switch_mm) +#ifdef __ARMEB__ +#define rl r3 +#define rh r2 +#else +#define rl r2 +#define rh r3 +#endif + /* * cpu_v7_set_pte_ext(ptep, pte) * @@ -73,13 +81,13 @@ ENDPROC(cpu_v7_switch_mm) */ ENTRY(cpu_v7_set_pte_ext) #ifdef CONFIG_MMU - tst r2, #L_PTE_VALID + tst rl, #L_PTE_VALID beq 1f - tst r3, #1 << (57 - 32) @ L_PTE_NONE - bicne r2, #L_PTE_VALID + tst rh, #1 << (57 - 32) @ L_PTE_NONE + bicne rl, #L_PTE_VALID bne 1f - tst r3, #1 << (55 - 32) @ L_PTE_DIRTY - orreq r2, #L_PTE_RDONLY + tst rh, #1 << (55 - 32) @ L_PTE_DIRTY + orreq rl, #L_PTE_RDONLY 1: strd r2, r3, [r0] ALT_SMP(W(nop)) ALT_UP (mcr p15, 0, r0, c7, c10, 1) @ flush_pte