From 23c1075ae83adaf14ea3f727c40368799f80bccc Mon Sep 17 00:00:00 2001 From: Kefeng Wang Date: Wed, 17 Mar 2021 23:08:38 +0800 Subject: riscv: Drop const annotation for sp The const annotation should not be used for 'sp', or it will become read only and lead to bad stack output. Fixes: dec822771b01 ("riscv: stacktrace: Move register keyword to beginning of declaration") Signed-off-by: Kefeng Wang Signed-off-by: Palmer Dabbelt --- arch/riscv/kernel/stacktrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c index 3f893c9d9d85..2b3e0cb90d78 100644 --- a/arch/riscv/kernel/stacktrace.c +++ b/arch/riscv/kernel/stacktrace.c @@ -14,7 +14,7 @@ #include -register const unsigned long sp_in_global __asm__("sp"); +register unsigned long sp_in_global __asm__("sp"); #ifdef CONFIG_FRAME_POINTER -- cgit v1.2.3 From 285a76bb2cf51b0c74c634f2aaccdb93e1f2a359 Mon Sep 17 00:00:00 2001 From: Ben Dooks Date: Mon, 29 Mar 2021 10:57:49 +0100 Subject: riscv: evaluate put_user() arg before enabling user access The header has a problem with put_user(a, ptr) if the 'a' is not a simple variable, such as a function. This can lead to the compiler producing code as so: 1: enable_user_access() 2: evaluate 'a' into register 'r' 3: put 'r' to 'ptr' 4: disable_user_acess() The issue is that 'a' is now being evaluated with the user memory protections disabled. So we try and force the evaulation by assigning 'x' to __val at the start, and hoping the compiler barriers in enable_user_access() do the job of ordering step 2 before step 1. This has shown up in a bug where 'a' sleeps and thus schedules out and loses the SR_SUM flag. This isn't sufficient to fully fix, but should reduce the window of opportunity. The first instance of this we found is in scheudle_tail() where the code does: $ less -N kernel/sched/core.c 4263 if (current->set_child_tid) 4264 put_user(task_pid_vnr(current), current->set_child_tid); Here, the task_pid_vnr(current) is called within the block that has enabled the user memory access. This can be made worse with KASAN which makes task_pid_vnr() a rather large call with plenty of opportunity to sleep. Signed-off-by: Ben Dooks Reported-by: syzbot+e74b94fe601ab9552d69@syzkaller.appspotmail.com Suggested-by: Arnd Bergman -- Changes since v1: - fixed formatting and updated the patch description with more info Changes since v2: - fixed commenting on __put_user() (schwab@linux-m68k.org) Change since v3: - fixed RFC in patch title. Should be ready to merge. Signed-off-by: Palmer Dabbelt --- arch/riscv/include/asm/uaccess.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/riscv/include/asm/uaccess.h b/arch/riscv/include/asm/uaccess.h index 824b2c9da75b..f944062c9d99 100644 --- a/arch/riscv/include/asm/uaccess.h +++ b/arch/riscv/include/asm/uaccess.h @@ -306,7 +306,9 @@ do { \ * data types like structures or arrays. * * @ptr must have pointer-to-simple-variable type, and @x must be assignable - * to the result of dereferencing @ptr. + * to the result of dereferencing @ptr. The value of @x is copied to avoid + * re-ordering where @x is evaluated inside the block that enables user-space + * access (thus bypassing user space protection if @x is a function). * * Caller must check the pointer with access_ok() before calling this * function. @@ -316,12 +318,13 @@ do { \ #define __put_user(x, ptr) \ ({ \ __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \ + __typeof__(*__gu_ptr) __val = (x); \ long __pu_err = 0; \ \ __chk_user_ptr(__gu_ptr); \ \ __enable_user_access(); \ - __put_user_nocheck(x, __gu_ptr, __pu_err); \ + __put_user_nocheck(__val, __gu_ptr, __pu_err); \ __disable_user_access(); \ \ __pu_err; \ -- cgit v1.2.3 From ac8d0b901f0033b783156ab2dc1a0e73ec42409b Mon Sep 17 00:00:00 2001 From: Zihao Yu Date: Wed, 17 Mar 2021 16:17:25 +0800 Subject: riscv,entry: fix misaligned base for excp_vect_table In RV64, the size of each entry in excp_vect_table is 8 bytes. If the base of the table is not 8-byte aligned, loading an entry in the table will raise a misaligned exception. Although such exception will be handled by opensbi/bbl, this still causes performance degradation. Signed-off-by: Zihao Yu Reviewed-by: Anup Patel Signed-off-by: Palmer Dabbelt --- arch/riscv/kernel/entry.S | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S index 744f3209c48d..76274a4a1d8e 100644 --- a/arch/riscv/kernel/entry.S +++ b/arch/riscv/kernel/entry.S @@ -447,6 +447,7 @@ ENDPROC(__switch_to) #endif .section ".rodata" + .align LGREG /* Exception vector table */ ENTRY(excp_vect_table) RISCV_PTR do_trap_insn_misaligned -- cgit v1.2.3 From 9d8c7d92015ece9a2139a259cef781a41845d2c0 Mon Sep 17 00:00:00 2001 From: Yang Li Date: Mon, 22 Mar 2021 16:38:36 +0800 Subject: riscv: remove unneeded semicolon Eliminate the following coccicheck warning: ./arch/riscv/mm/kasan_init.c:219:2-3: Unneeded semicolon Reported-by: Abaci Robot Signed-off-by: Yang Li Signed-off-by: Palmer Dabbelt --- arch/riscv/mm/kasan_init.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/riscv/mm/kasan_init.c b/arch/riscv/mm/kasan_init.c index 4f85c6d0ddf8..937d13ce9ab8 100644 --- a/arch/riscv/mm/kasan_init.c +++ b/arch/riscv/mm/kasan_init.c @@ -216,7 +216,7 @@ void __init kasan_init(void) break; kasan_populate(kasan_mem_to_shadow(start), kasan_mem_to_shadow(end)); - }; + } for (i = 0; i < PTRS_PER_PTE; i++) set_pte(&kasan_early_shadow_pte[i], -- cgit v1.2.3 From 1adbc2941eee8acbe3c7dc6b51cdbc5a9bf19565 Mon Sep 17 00:00:00 2001 From: Kefeng Wang Date: Tue, 30 Mar 2021 21:25:31 +0800 Subject: riscv: Make NUMA depend on MMU NUMA is useless when NOMMU, and it leads some build error, make it depend on MMU. Reported-by: kernel test robot Signed-off-by: Kefeng Wang Signed-off-by: Palmer Dabbelt --- arch/riscv/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 87d7b52f278f..0d0cf67359cb 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -314,7 +314,7 @@ endchoice # Common NUMA Features config NUMA bool "NUMA Memory Allocation and Scheduler Support" - depends on SMP + depends on SMP && MMU select GENERIC_ARCH_NUMA select OF_NUMA select ARCH_SUPPORTS_NUMA_BALANCING -- cgit v1.2.3