The following commit has been merged into the efi/urgent branch of tip: Commit-ID: b418d660bb9798d2249ac6a46c844389ef50b6a5 Gitweb: https://git.kernel.org/tip/b418d660bb9798d2249ac6a46c844389ef50b6a5 Author: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> AuthorDate: Fri, 06 Dec 2019 16:55:42 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitterDate: Sun, 08 Dec 2019 12:42:19 +01:00 efi/earlycon: Remap entire framebuffer after page initialization When commit: 69c1f396f25b ("efi/x86: Convert x86 EFI earlyprintk into generic earlycon implementation") moved the x86 specific EFI earlyprintk implementation to a shared location, it also tweaked the behaviour. In particular, it dropped a trick with full framebuffer remapping after page initialization, leading to two regressions: 1) very slow scrolling after page initialization, 2) kernel hang when the 'keep_bootcon' command line argument is passed. Putting the tweak back fixes #2 and mitigates #1, i.e., it limits the slow behavior to the early boot stages, presumably due to eliminating heavy map()/unmap() operations per each pixel line on the screen. [ ardb: ensure efifb is unmapped again unless keep_bootcon is in effect. ] [ mingo: speling fixes. ] Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx> Cc: Arvind Sankar <nivedita@xxxxxxxxxxxx> Cc: Bhupesh Sharma <bhsharma@xxxxxxxxxx> Cc: Masayoshi Mizuma <m.mizuma@xxxxxxxxxxxxxx> Cc: linux-efi@xxxxxxxxxxxxxxx Fixes: 69c1f396f25b ("efi/x86: Convert x86 EFI earlyprintk into generic earlycon implementation") Link: https://lkml.kernel.org/r/20191206165542.31469-7-ardb@xxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- drivers/firmware/efi/earlycon.c | 40 ++++++++++++++++++++++++++++++++- 1 file changed, 40 insertions(+) diff --git a/drivers/firmware/efi/earlycon.c b/drivers/firmware/efi/earlycon.c index c9a0efc..d4077db 100644 --- a/drivers/firmware/efi/earlycon.c +++ b/drivers/firmware/efi/earlycon.c @@ -13,18 +13,57 @@ #include <asm/early_ioremap.h> +static const struct console *earlycon_console __initdata; static const struct font_desc *font; static u32 efi_x, efi_y; static u64 fb_base; static pgprot_t fb_prot; +static void *efi_fb; + +/* + * EFI earlycon needs to use early_memremap() to map the framebuffer. + * But early_memremap() is not usable for 'earlycon=efifb keep_bootcon', + * memremap() should be used instead. memremap() will be available after + * paging_init() which is earlier than initcall callbacks. Thus adding this + * early initcall function early_efi_map_fb() to map the whole EFI framebuffer. + */ +static int __init efi_earlycon_remap_fb(void) +{ + /* bail if there is no bootconsole or it has been disabled already */ + if (!earlycon_console || !(earlycon_console->flags & CON_ENABLED)) + return 0; + + if (pgprot_val(fb_prot) == pgprot_val(PAGE_KERNEL)) + efi_fb = memremap(fb_base, screen_info.lfb_size, MEMREMAP_WB); + else + efi_fb = memremap(fb_base, screen_info.lfb_size, MEMREMAP_WC); + + return efi_fb ? 0 : -ENOMEM; +} +early_initcall(efi_earlycon_remap_fb); + +static int __init efi_earlycon_unmap_fb(void) +{ + /* unmap the bootconsole fb unless keep_bootcon has left it enabled */ + if (efi_fb && !(earlycon_console->flags & CON_ENABLED)) + memunmap(efi_fb); + return 0; +} +late_initcall(efi_earlycon_unmap_fb); static __ref void *efi_earlycon_map(unsigned long start, unsigned long len) { + if (efi_fb) + return efi_fb + start; + return early_memremap_prot(fb_base + start, len, pgprot_val(fb_prot)); } static __ref void efi_earlycon_unmap(void *addr, unsigned long len) { + if (efi_fb) + return; + early_memunmap(addr, len); } @@ -201,6 +240,7 @@ static int __init efi_earlycon_setup(struct earlycon_device *device, efi_earlycon_scroll_up(); device->con->write = efi_earlycon_write; + earlycon_console = device->con; return 0; } EARLYCON_DECLARE(efifb, efi_earlycon_setup);
