On Thu, Jan 03, 2013 at 03:50:55PM +0000, Matt Fleming wrote: > On Wed, 2013-01-02 at 15:09 -0600, Robin Holt wrote: > > On Wed, Jan 02, 2013 at 01:13:43PM -0600, Nathan Zimmer wrote: > > > On 01/02/2013 12:04 PM, H. Peter Anvin wrote: > > > >On 01/02/2013 09:21 AM, Nathan Zimmer wrote: > > > >>I am getting an early boot problem. It only happens on the larger of the > > > >>machines I haven't seen it crop up on machines with more then 512 GB of > > > >>ram. > > > >>It shows in the latest linus kernel too. > > > >> > > > >>I am (wildly) guessing that what is happening is that the new_memmap > > > >>that is > > > >>being passed to bios is somehow placed incorrectly. > > > >>I have come up with a workaround. By placing it the DMA area the issue > > > >>goes > > > >>away but that doesn't seem like a real fix. > > > >> > > > >What does your memory map look like? > > > > We reported this a few times (Russ Anderson and I both). The problem is > > at the point in boot where the efi_enter_virtual_mode callback is, there > > is no identity mapping for most of memory. If the allocation happens > > to be above the 512GB (or maybe something lower than that) point, the > > BIOS is not able to address this via the physical address passed to it. > > Right, looks like efi_call_phys_prelog() needs rewriting to install a > proper identity mapping that actually addresses *all* of available > memory, instead of just the first PGDIR_SIZE bytes. > >
Ok here is what Robin and I came up with >From c96406c36a45de25ac83681971b64d48096288e2 Mon Sep 17 00:00:00 2001 From: Nathan Zimmer <[email protected]> Date: Thu, 3 Jan 2013 15:41:10 -0600 Subject: [PATCH] Pass a proper identity mapping in efi_call_phys_prelog Update efi_call_phys_prelog to install an identity mapping of all available memory. This corrects a bug on very large systems with more then 512 GB in which bios would not be able to access addresses above not in the mapping. The result is a crash that looks much like this. BUG: unable to handle kernel paging request at 000000effd870020 IP: [<0000000078bce331>] 0x78bce330 PGD 0 Oops: 0000 [#1] SMP Modules linked in: CPU 0 Pid: 0, comm: swapper/0 Tainted: G W 3.8.0-rc1-next-20121224-medusa_ntz+ #2 Intel Corp. Stoutland Platform RIP: 0010:[<0000000078bce331>] [<0000000078bce331>] 0x78bce330 RSP: 0000:ffffffff81601d28 EFLAGS: 00010006 RAX: 0000000078b80e18 RBX: 0000000000000004 RCX: 0000000000000004 RDX: 0000000078bcf958 RSI: 0000000000002400 RDI: 8000000000000000 RBP: 0000000078bcf760 R08: 000000effd870000 R09: 0000000000000000 R10: 0000000000000000 R11: 00000000000000c3 R12: 0000000000000030 R13: 000000effd870000 R14: 0000000000000000 R15: ffff88effd870000 FS: 0000000000000000(0000) GS:ffff88effe400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000effd870020 CR3: 000000000160c000 CR4: 00000000000006b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process swapper/0 (pid: 0, threadinfo ffffffff81600000, task ffffffff81614400) Stack: 0000000078b80d18 0000000000000004 0000000078bced7b ffff880078b81fff 0000000000000000 0000000000000082 0000000078bce3a8 0000000000002400 0000000060000202 0000000078b80da0 0000000078bce45d ffffffff8107cb5a Call Trace: [<ffffffff8107cb5a>] ? on_each_cpu+0x77/0x83 [<ffffffff8102f4eb>] ? change_page_attr_set_clr+0x32f/0x3ed [<ffffffff81035946>] ? efi_call4+0x46/0x80 [<ffffffff816c5abb>] ? efi_enter_virtual_mode+0x1f5/0x305 [<ffffffff816aeb24>] ? start_kernel+0x34a/0x3d2 [<ffffffff816ae5ed>] ? repair_env_string+0x60/0x60 [<ffffffff816ae2be>] ? x86_64_start_reservations+0xba/0xc1 [<ffffffff816ae120>] ? early_idt_handlers+0x120/0x120 [<ffffffff816ae419>] ? x86_64_start_kernel+0x154/0x163 Code: Bad RIP value. RIP [<0000000078bce331>] 0x78bce330 RSP <ffffffff81601d28> CR2: 000000effd870020 ---[ end trace ead828934fef5eab ]--- Cc: Matt Fleming <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Signed-off-by: Nathan Zimmer <[email protected]> Signed-off-by: Robin Holt <[email protected]> --- arch/x86/platform/efi/efi_64.c | 23 ++++++++++++++++++----- 1 files changed, 18 insertions(+), 5 deletions(-) diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c index 95fd505..79d54d7 100644 --- a/arch/x86/platform/efi/efi_64.c +++ b/arch/x86/platform/efi/efi_64.c @@ -38,7 +38,7 @@ #include <asm/cacheflush.h> #include <asm/fixmap.h> -static pgd_t save_pgd __initdata; +static pgd_t *save_pgd __initdata; static unsigned long efi_flags __initdata; static void __init early_code_mapping_set_exec(int executable) @@ -61,13 +61,22 @@ static void __init early_code_mapping_set_exec(int executable) void __init efi_call_phys_prelog(void) { unsigned long vaddress; + int pgd; + int n_pgds; early_code_mapping_set_exec(1); local_irq_save(efi_flags); - vaddress = (unsigned long)__va(0x0UL); - save_pgd = *pgd_offset_k(0x0UL); - set_pgd(pgd_offset_k(0x0UL), *pgd_offset_k(vaddress)); + + n_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT), PGDIR_SIZE); + save_pgd = kmalloc(n_pgds * sizeof(pgd_t), GFP_KERNEL); + + for (pgd = 0; pgd < n_pgds; pgd++) { + save_pgd[pgd] = *pgd_offset_k(pgd * PGDIR_SIZE); + vaddress = (unsigned long)__va(pgd * PGDIR_SIZE); + set_pgd(pgd_offset_k(j * PGDIR_SIZE), *pgd_offset_k(vaddress)); + } __flush_tlb_all(); + } void __init efi_call_phys_epilog(void) @@ -75,7 +84,11 @@ void __init efi_call_phys_epilog(void) /* * After the lock is released, the original page table is restored. */ - set_pgd(pgd_offset_k(0x0UL), save_pgd); + int pgd; + int n_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT) , PGDIR_SIZE); + for (pgd = 0; pgd < n_pgds; pgd++) + set_pgd(pgd_offset_k(pgd * PGDIR_SIZE), save_pgd[pgd]); + kfree(save_pgd); __flush_tlb_all(); local_irq_restore(efi_flags); early_code_mapping_set_exec(0); -- 1.6.0.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
