From c21f5a9ed85ca3e914ca11f421677ae9ae0d04b0 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Mon, 3 Jun 2019 13:00:51 +0000 Subject: [PATCH] powerpc/32s: fix booting with CONFIG_PPC_EARLY_DEBUG_BOOTX When booting through OF, setup_disp_bat() does nothing because disp_BAT are not set. By change, it used to work because BOOTX buffer is mapped 1:1 at address 0x81000000 by the bootloader, and btext_setup_display() sets virt addr same as phys addr. But since commit 215b823707ce ("powerpc/32s: set up an early static hash table for KASAN."), a temporary page table overrides the bootloader mapping. This 0x81000000 is also problematic with the newly implemented Kernel Userspace Access Protection (KUAP) because it is within user address space. This patch fixes those issues by properly setting disp_BAT through a call to btext_prepare_BAT(), allowing setup_disp_bat() to properly setup BAT3 for early bootx screen buffer access. Reported-by: Mathieu Malaterre Fixes: 215b823707ce ("powerpc/32s: set up an early static hash table for KASAN.") Signed-off-by: Christophe Leroy Tested-by: Mathieu Malaterre Signed-off-by: Michael Ellerman --- arch/powerpc/include/asm/btext.h | 4 ++++ arch/powerpc/kernel/prom_init.c | 1 + arch/powerpc/kernel/prom_init_check.sh | 2 +- 3 files changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/include/asm/btext.h b/arch/powerpc/include/asm/btext.h index 3ffad03..461b0f1 100644 --- a/arch/powerpc/include/asm/btext.h +++ b/arch/powerpc/include/asm/btext.h @@ -13,7 +13,11 @@ extern void btext_update_display(unsigned long phys, int width, int height, int depth, int pitch); extern void btext_setup_display(int width, int height, int depth, int pitch, unsigned long address); +#ifdef CONFIG_PPC32 extern void btext_prepare_BAT(void); +#else +static inline void btext_prepare_BAT(void) { } +#endif extern void btext_map(void); extern void btext_unmap(void); diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c index 00682b8..61795c3 100644 --- a/arch/powerpc/kernel/prom_init.c +++ b/arch/powerpc/kernel/prom_init.c @@ -2340,6 +2340,7 @@ static void __init prom_check_displays(void) prom_printf("W=%d H=%d LB=%d addr=0x%x\n", width, height, pitch, addr); btext_setup_display(width, height, 8, pitch, addr); + btext_prepare_BAT(); } #endif /* CONFIG_PPC_EARLY_DEBUG_BOOTX */ } diff --git a/arch/powerpc/kernel/prom_init_check.sh b/arch/powerpc/kernel/prom_init_check.sh index 4cac45c..acf63ad 100644 --- a/arch/powerpc/kernel/prom_init_check.sh +++ b/arch/powerpc/kernel/prom_init_check.sh @@ -27,7 +27,7 @@ fi WHITELIST="add_reloc_offset __bss_start __bss_stop copy_and_flush _end enter_prom $MEM_FUNCS reloc_offset __secondary_hold __secondary_hold_acknowledge __secondary_hold_spinloop __start -logo_linux_clut224 +logo_linux_clut224 btext_prepare_BAT reloc_got2 kernstart_addr memstart_addr linux_banner _stext __prom_init_toc_start __prom_init_toc_end btext_setup_display TOC." -- 2.7.4