forked from Minki/linux
ARM: 8037/1: mm: support big-endian page tables
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 [<c000f5f0>] (unwind_backtrace+0x0/0x11c) from [<c000cbc4>] (show_stack+0x10/0x14) [<c000cbc4>] (show_stack+0x10/0x14) from [<c009e448>] (bad_page+0xd4/0x104) [<c009e448>] (bad_page+0xd4/0x104) from [<c009e520>] (free_pages_prepare+0xa8/0x14c) [<c009e520>] (free_pages_prepare+0xa8/0x14c) from [<c009f8ec>] (free_hot_cold_page+0x18/0xf0) [<c009f8ec>] (free_hot_cold_page+0x18/0xf0) from [<c00b5444>] (handle_pte_fault+0xcf4/0xdc8) [<c00b5444>] (handle_pte_fault+0xcf4/0xdc8) from [<c00b6458>] (handle_mm_fault+0xf4/0x120) [<c00b6458>] (handle_mm_fault+0xf4/0x120) from [<c0013754>] (do_page_fault+0xfc/0x354) [<c0013754>] (do_page_fault+0xfc/0x354) from [<c0008400>] (do_DataAbort+0x2c/0x90) [<c0008400>] (do_DataAbort+0x2c/0x90) from [<c0008fb4>] (__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. CC stable <stable@vger.kernel.org> Signed-off-by: Jianguo Wu <wujianguo@huawei.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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@ -64,6 +64,14 @@ ENTRY(cpu_v7_switch_mm)
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mov pc, lr
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ENDPROC(cpu_v7_switch_mm)
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#ifdef __ARMEB__
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#define rl r3
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#define rh r2
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#else
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#define rl r2
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#define rh r3
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#endif
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/*
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* cpu_v7_set_pte_ext(ptep, pte)
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*
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@ -73,13 +81,13 @@ ENDPROC(cpu_v7_switch_mm)
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*/
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ENTRY(cpu_v7_set_pte_ext)
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#ifdef CONFIG_MMU
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tst r2, #L_PTE_VALID
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tst rl, #L_PTE_VALID
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beq 1f
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tst r3, #1 << (57 - 32) @ L_PTE_NONE
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bicne r2, #L_PTE_VALID
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tst rh, #1 << (57 - 32) @ L_PTE_NONE
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bicne rl, #L_PTE_VALID
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bne 1f
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tst r3, #1 << (55 - 32) @ L_PTE_DIRTY
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orreq r2, #L_PTE_RDONLY
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tst rh, #1 << (55 - 32) @ L_PTE_DIRTY
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orreq rl, #L_PTE_RDONLY
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1: strd r2, r3, [r0]
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ALT_SMP(W(nop))
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ALT_UP (mcr p15, 0, r0, c7, c10, 1) @ flush_pte
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