On 18/12/15 13:56, Matt Fleming wrote: > (Pulling in Ingo and Juergen because of commit 954e12f7a800) > > On Thu, 17 Dec, at 05:30:45PM, Môshe van der Sterre wrote: >> Hello Sai and others, >> >> The change to use early_mem*() instead of early_io*() in 50a0cb56 does not >> work on my machine. Last week I discussed some BGRT changes and I created a >> patch for that, but can't test it on efi-next because of this. >> >> I get this (when booting 50a0cb56, without any of my changes): >> [ 0.026936] ------------[ cut here ]------------ >> [ 0.026941] WARNING: CPU: 0 PID: 0 at mm/early_ioremap.c:137 >> __early_ioremap+0x102/0x1bb() >> [ 0.026941] Modules linked in: >> [ 0.026944] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.0-rc1 #2 >> [ 0.026945] Hardware name: Dell Inc. XPS 13 9343/09K8G1, BIOS A05 >> 07/14/2015 >> [ 0.026946] 0000000000000000 900f03d5a116524d ffffffff81c03e60 >> ffffffff813a3fff >> [ 0.026948] 0000000000000000 ffffffff81c03e98 ffffffff810a0852 >> 00000000d7b76000 >> [ 0.026949] 0000000000000000 0000000000000001 0000000000000001 >> 000000000000017c >> [ 0.026951] Call Trace: >> [ 0.026955] [<ffffffff813a3fff>] dump_stack+0x44/0x55 >> [ 0.026958] [<ffffffff810a0852>] warn_slowpath_common+0x82/0xc0 >> [ 0.026959] [<ffffffff810a099a>] warn_slowpath_null+0x1a/0x20 >> [ 0.026961] [<ffffffff81d8c395>] __early_ioremap+0x102/0x1bb >> [ 0.026962] [<ffffffff81d8c602>] early_memremap+0x13/0x15 >> [ 0.026964] [<ffffffff81d78361>] efi_bgrt_init+0x162/0x1ad >> [ 0.026966] [<ffffffff81d778ec>] efi_late_init+0x9/0xb >> [ 0.026968] [<ffffffff81d58ff5>] start_kernel+0x46f/0x49f >> [ 0.026970] [<ffffffff81d58120>] ? early_idt_handler_array+0x120/0x120 >> [ 0.026972] [<ffffffff81d58339>] x86_64_start_reservations+0x2a/0x2c >> [ 0.026974] [<ffffffff81d58485>] x86_64_start_kernel+0x14a/0x16d >> [ 0.026977] ---[ end trace f9b3812eb8e24c58 ]--- >> [ 0.026978] efi_bgrt: Ignoring BGRT: failed to map image memory >> >> This is the second early_memremap call in efi_bgrt_init triggering >> WARN_ON(nrpages > NR_FIX_BTMAPS). Can you comment on this? > > Hmm... yeah NR_FIX_BTMAPS == 64, so early_memremap() is limited to > mapping ~200KB at once. That's not very big, your BGRT data is likely > much larger than that. > > Obviously we can't use efi_lookup_mapped_addr() any more, so it makes > sense to come up with a much robust way to memremap the BGRT image. > > The immediate solution that comes to mind is using memremap() instead > of the early_* version, since the late version won't use the FIXMAP > area and will allow us to map a much larger region into the kernel > virtual address space. > > Digging through the history it appears I was the one who made the > switch from ioremap() to early_memremap() in commit 081cd62a010f > ("x86/efi: Allow mapping BGRT on x86-32"), which I suspect was because > a generic memremap() implementation didn't exist at the time. Dan > Williams introduced one in Aug 2015 with commit 92281dee825f ("arch: > introduce memremap()"). > > Somewhat surprisingly, Juergen switched the BGRT driver from > early_memremap() to early_ioremap() in commit 954e12f7a800 ("x86/mm, > efi: Use early_ioremap() in arch/x86/platform/efi/efi-bgrt.c") > although I can't figure out why because this isn't I/O memory. And now > we're attempting to switch it back. > > Juergen, could you provide a rationale for commit 954e12f7a800? All > the commit message says is that it's "an I/O-area", but that isn't > true. I was hunting down some inconsistencies regarding early_[mem|io]remap. I patched places where the remap and unmap calls where of different type (e.g. a pair of early_memremap() / early_iounmap()). Maybe I was fooled here by all other names hinting towards io instead of mem (ioremapped, memcpy_fromio()). Juergen > > In the meantime Môshe, could you try this patch ontop of the EFI > 'next' branch? (Note it may not work/compile, but you get the gist) > > --- > > diff --git a/arch/x86/platform/efi/efi-bgrt.c b/arch/x86/platform/efi/efi-bgrt.c > index bf51f4c02562..b0970661870a 100644 > --- a/arch/x86/platform/efi/efi-bgrt.c > +++ b/arch/x86/platform/efi/efi-bgrt.c > @@ -72,14 +72,14 @@ void __init efi_bgrt_init(void) > return; > } > > - image = early_memremap(bgrt_tab->image_address, sizeof(bmp_header)); > + image = memremap(bgrt_tab->image_address, sizeof(bmp_header), MEMREMAP_WB); > if (!image) { > pr_err("Ignoring BGRT: failed to map image header memory\n"); > return; > } > > memcpy(&bmp_header, image, sizeof(bmp_header)); > - early_memunmap(image, sizeof(bmp_header)); > + memunmap(image); > bgrt_image_size = bmp_header.size; > > bgrt_image = kmalloc(bgrt_image_size, GFP_KERNEL | __GFP_NOWARN); > @@ -89,7 +89,7 @@ void __init efi_bgrt_init(void) > return; > } > > - image = early_memremap(bgrt_tab->image_address, bmp_header.size); > + image = memremap(bgrt_tab->image_address, bmp_header.size, MEMREMAP_WB); > if (!image) { > pr_err("Ignoring BGRT: failed to map image memory\n"); > kfree(bgrt_image); > @@ -98,5 +98,5 @@ void __init efi_bgrt_init(void) > } > > memcpy(bgrt_image, image, bgrt_image_size); > - early_memunmap(image, bmp_header.size); > + memunmap(image); > } > -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html