From dbee9c9c45846f003ec2f819710c2f4835630a6a Mon Sep 17 00:00:00 2001 From: Alan Kao Date: Fri, 22 Mar 2019 14:37:04 +0800 Subject: [PATCH 1/4] riscv: fix accessing 8-byte variable from RV32 A memory save operation to 8-byte variable in RV32 is divided into two sw instructions in the put_user macro. The current fixup returns execution flow to the second sw instead of the one after it. This patch fixes this fixup code according to the load access part. Signed-off-by: Alan Kao Cc: Greentime Hu Cc: Vincent Chen Signed-off-by: Palmer Dabbelt --- arch/riscv/include/asm/uaccess.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/riscv/include/asm/uaccess.h b/arch/riscv/include/asm/uaccess.h index a00168b980d2..fb53a8089e76 100644 --- a/arch/riscv/include/asm/uaccess.h +++ b/arch/riscv/include/asm/uaccess.h @@ -300,7 +300,7 @@ do { \ " .balign 4\n" \ "4:\n" \ " li %0, %6\n" \ - " jump 2b, %1\n" \ + " jump 3b, %1\n" \ " .previous\n" \ " .section __ex_table,\"a\"\n" \ " .balign " RISCV_SZPTR "\n" \ From 387181dcdb6c1ee254efab4744846a7a53d4c4cb Mon Sep 17 00:00:00 2001 From: Anup Patel Date: Tue, 26 Mar 2019 08:03:47 +0000 Subject: [PATCH 2/4] RISC-V: Always compile mm/init.c with cmodel=medany and notrace The Linux RISC-V 32bit kernel is broken after we moved setup_vm() from kernel/setup.c to mm/init.c because Linux RISC-V 32bit kernel by default uses cmodel=medlow which results in a non-position-independent setup_vm(). This patch fixes Linux RISC-V 32bit kernel booting by: 1. Forcing cmodel=medany for mm/init.c 2. Moving remaing MM-related stuff va_pa_offset, pfn_base and empty_zero_page from kernel/setup.c to mm/init.c Further, the setup_vm() cannot handle GCC instrumentation for FTRACE so we disable it for mm/init.c by not using "-pg" compiler flag. Fixes: 6f1e9e946f0b ("RISC-V: Move setup_vm() to mm/init.c") Suggested-by: Christoph Hellwig Suggested-by: Mike Rapoport Signed-off-by: Anup Patel Reviewed-by: Mike Rapoport Reviewed-by: Christoph Hellwig Signed-off-by: Palmer Dabbelt --- arch/riscv/kernel/Makefile | 3 --- arch/riscv/kernel/setup.c | 8 -------- arch/riscv/mm/Makefile | 6 ++++++ arch/riscv/mm/init.c | 28 ++++++++++++++++++++++++++++ 4 files changed, 34 insertions(+), 11 deletions(-) diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile index f13f7f276639..598568168d35 100644 --- a/arch/riscv/kernel/Makefile +++ b/arch/riscv/kernel/Makefile @@ -4,7 +4,6 @@ ifdef CONFIG_FTRACE CFLAGS_REMOVE_ftrace.o = -pg -CFLAGS_REMOVE_setup.o = -pg endif extra-y += head.o @@ -29,8 +28,6 @@ obj-y += vdso.o obj-y += cacheinfo.o obj-y += vdso/ -CFLAGS_setup.o := -mcmodel=medany - obj-$(CONFIG_FPU) += fpu.o obj-$(CONFIG_SMP) += smpboot.o obj-$(CONFIG_SMP) += smp.o diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c index ecb654f6a79e..540a331d1376 100644 --- a/arch/riscv/kernel/setup.c +++ b/arch/riscv/kernel/setup.c @@ -48,14 +48,6 @@ struct screen_info screen_info = { }; #endif -unsigned long va_pa_offset; -EXPORT_SYMBOL(va_pa_offset); -unsigned long pfn_base; -EXPORT_SYMBOL(pfn_base); - -unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss; -EXPORT_SYMBOL(empty_zero_page); - /* The lucky hart to first increment this variable will boot the other cores */ atomic_t hart_lottery; unsigned long boot_cpu_hartid; diff --git a/arch/riscv/mm/Makefile b/arch/riscv/mm/Makefile index eb22ab49b3e0..b68aac701803 100644 --- a/arch/riscv/mm/Makefile +++ b/arch/riscv/mm/Makefile @@ -1,3 +1,9 @@ + +CFLAGS_init.o := -mcmodel=medany +ifdef CONFIG_FTRACE +CFLAGS_REMOVE_init.o = -pg +endif + obj-y += init.o obj-y += fault.o obj-y += extable.o diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index b379a75ac6a6..5fd8c922e1c2 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -25,6 +25,10 @@ #include #include +unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] + __page_aligned_bss; +EXPORT_SYMBOL(empty_zero_page); + static void __init zone_sizes_init(void) { unsigned long max_zone_pfns[MAX_NR_ZONES] = { 0, }; @@ -143,6 +147,11 @@ void __init setup_bootmem(void) } } +unsigned long va_pa_offset; +EXPORT_SYMBOL(va_pa_offset); +unsigned long pfn_base; +EXPORT_SYMBOL(pfn_base); + pgd_t swapper_pg_dir[PTRS_PER_PGD] __page_aligned_bss; pgd_t trampoline_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE); @@ -172,6 +181,25 @@ void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot) } } +/* + * setup_vm() is called from head.S with MMU-off. + * + * Following requirements should be honoured for setup_vm() to work + * correctly: + * 1) It should use PC-relative addressing for accessing kernel symbols. + * To achieve this we always use GCC cmodel=medany. + * 2) The compiler instrumentation for FTRACE will not work for setup_vm() + * so disable compiler instrumentation when FTRACE is enabled. + * + * Currently, the above requirements are honoured by using custom CFLAGS + * for init.o in mm/Makefile. + */ + +#ifndef __riscv_cmodel_medany +#error "setup_vm() is called from head.S before relocate so it should " + "not use absolute addressing." +#endif + asmlinkage void __init setup_vm(void) { extern char _start; From ff0e2a7bd13f7c332d7f09ff45d08df4bf512ce0 Mon Sep 17 00:00:00 2001 From: Anup Patel Date: Fri, 22 Mar 2019 10:04:44 +0000 Subject: [PATCH 3/4] RISC-V: Fix FIXMAP_TOP to avoid overlap with VMALLOC area The FIXMAP area overlaps with VMALLOC area in Linux-5.1-rc1 hence we get below warning in Linux RISC-V 32bit kernel. This warning does not show-up in Linux RISC-V 64bit kernel due to large VMALLOC area. WARNING: CPU: 0 PID: 22 at mm/vmalloc.c:150 vmap_page_range_noflush+0x134/0x15c Modules linked in: CPU: 0 PID: 22 Comm: kworker/0:1 Not tainted 5.1.0-rc1-00005-gebc2f658040e #1 Workqueue: events pcpu_balance_workfn Call Trace: [] walk_stackframe+0x0/0xa0 [] show_stack+0x28/0x32 [] dump_stack+0x62/0x7e [] __warn+0x98/0xce [] warn_slowpath_null+0x2e/0x3c [] vmap_page_range_noflush+0x134/0x15c [] map_kernel_range_noflush+0xc/0x14 [] pcpu_populate_chunk+0x19e/0x236 [] pcpu_balance_workfn+0x448/0x464 [] process_one_work+0x16c/0x2ea [] worker_thread+0xf2/0x3b2 [] kthread+0xce/0xdc [] ret_from_exception+0x0/0xc This patch fixes above warning by placing FIXMAP area below VMALLOC area. Fixes: f2c17aabc917 ("RISC-V: Implement compile-time fixed mappings") Signed-off-by: Anup Patel Reviewed-by: Christoph Hellwig Signed-off-by: Palmer Dabbelt --- arch/riscv/include/asm/fixmap.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/riscv/include/asm/fixmap.h b/arch/riscv/include/asm/fixmap.h index 57afe604b495..c207f6634b91 100644 --- a/arch/riscv/include/asm/fixmap.h +++ b/arch/riscv/include/asm/fixmap.h @@ -26,7 +26,7 @@ enum fixed_addresses { }; #define FIXADDR_SIZE (__end_of_fixed_addresses * PAGE_SIZE) -#define FIXADDR_TOP (PAGE_OFFSET) +#define FIXADDR_TOP (VMALLOC_START) #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) #define FIXMAP_PAGE_IO PAGE_KERNEL From da4ed37873918eeb4e8db7f0cf55e0a7e18788c3 Mon Sep 17 00:00:00 2001 From: Joe Perches Date: Thu, 7 Mar 2019 15:56:34 -0800 Subject: [PATCH 4/4] RISC-V: Use IS_ENABLED(CONFIG_CMODEL_MEDLOW) IS_ENABLED should generally use CONFIG_ prefaced symbols and it doesn't appear as if there is a CMODEL_MEDLOW define. Signed-off-by: Joe Perches Reviewed-by: Christoph Hellwig Signed-off-by: Palmer Dabbelt --- arch/riscv/kernel/module.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c index 7dd308129b40..2872edce894d 100644 --- a/arch/riscv/kernel/module.c +++ b/arch/riscv/kernel/module.c @@ -141,7 +141,7 @@ static int apply_r_riscv_hi20_rela(struct module *me, u32 *location, { s32 hi20; - if (IS_ENABLED(CMODEL_MEDLOW)) { + if (IS_ENABLED(CONFIG_CMODEL_MEDLOW)) { pr_err( "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n", me->name, (long long)v, location);