kernel.git/arch/riscv/kernel/entry.S, branch linux-6.4.y

riscv: entry: Consolidate general regs saving/restoring

2023-03-23T15:47:03Z

Consolidate the saving/restoring GPs (except zero, ra, sp, gp, tp and t0) into save_from_x6_to_x31/restore_from_x6_to_x31 macros. No functional change intended. Signed-off-by: Jisheng Zhang Reviewed-by: Guo Ren Reviewed-by: Björn Töpel Tested-by: Guo Ren Signed-off-by: Guo Ren Link: https://lore.kernel.org/r/20230222033021.983168-8-guoren@kernel.org Signed-off-by: Palmer Dabbelt

riscv: entry: Consolidate ret_from_kernel_thread into ret_from_fork

2023-03-23T15:47:02Z

The ret_from_kernel_thread() behaves similarly with ret_from_fork(), the only difference is whether call the fn(arg) or not, this can be achieved by testing fn is NULL or not, I.E s0 is 0 or not. Many architectures have done the same thing, it makes entry.S more clean. Signed-off-by: Jisheng Zhang Reviewed-by: Björn Töpel Reviewed-by: Guo Ren Tested-by: Guo Ren Signed-off-by: Guo Ren Link: https://lore.kernel.org/r/20230222033021.983168-7-guoren@kernel.org Signed-off-by: Palmer Dabbelt

riscv: entry: Convert to generic entry

2023-03-23T15:47:00Z

This patch converts riscv to use the generic entry infrastructure from kernel/entry/*. The generic entry makes maintainers' work easier and codes more elegant. Here are the changes: - More clear entry.S with handle_exception and ret_from_exception - Get rid of complex custom signal implementation - Move syscall procedure from assembly to C, which is much more readable. - Connect ret_from_fork & ret_from_kernel_thread to generic entry. - Wrap with irqentry_enter/exit and syscall_enter/exit_from_user_mode - Use the standard preemption code instead of custom Suggested-by: Huacai Chen Reviewed-by: Björn Töpel Tested-by: Yipeng Zou Tested-by: Jisheng Zhang Signed-off-by: Guo Ren Signed-off-by: Guo Ren Cc: Ben Hutchings Link: https://lore.kernel.org/r/20230222033021.983168-5-guoren@kernel.org Signed-off-by: Palmer Dabbelt

Merge patch series "RISC-V: Align the shadow stack"

2022-12-12T17:30:37Z

Palmer Dabbelt says: This contains a pair of cleanups that depend on a fix that has already landed upstream. * b4-shazam-merge: RISC-V: Add some comments about the shadow and overflow stacks RISC-V: Align the shadow stack riscv: fix race when vmap stack overflow Link: https://lore.kernel.org/r/20221130023515.20217-1-palmer@rivosinc.com Signed-off-by: Palmer Dabbelt

Merge patch "RISC-V: Fix unannoted hardirqs-on in return to userspace slow-path"

2022-12-08T23:31:44Z

I'm merging this in as a single patch to make it easier to handle the backports. * b4-shazam-merge: RISC-V: Fix unannoted hardirqs-on in return to userspace slow-path Link: https://lore.kernel.org/r/20221111223108.1976562-1-abrestic@rivosinc.com Signed-off-by: Palmer Dabbelt

RISC-V: Fix unannoted hardirqs-on in return to userspace slow-path

2022-12-08T23:31:41Z

The return to userspace path in entry.S may enable interrupts without the corresponding lockdep annotation, producing a splat[0] when DEBUG_LOCKDEP is enabled. Simply calling __trace_hardirqs_on() here gets a bit messy due to the use of RA to point back to ret_from_exception, so just move the whole slow-path loop into C. It's more readable and it lets us use local_irq_{enable,disable}(), avoiding the need for manual annotations altogether. [0]: ------------[ cut here ]------------ DEBUG_LOCKS_WARN_ON(!lockdep_hardirqs_enabled()) WARNING: CPU: 2 PID: 1 at kernel/locking/lockdep.c:5512 check_flags+0x10a/0x1e0 Modules linked in: CPU: 2 PID: 1 Comm: init Not tainted 6.1.0-rc4-00160-gb56b6e2b4f31 #53 Hardware name: riscv-virtio,qemu (DT) epc : check_flags+0x10a/0x1e0 ra : check_flags+0x10a/0x1e0 status: 0000000200000100 badaddr: 0000000000000000 cause: 0000000000000003 [] lock_is_held_type+0x78/0x14e [] __might_resched+0x26/0x22c [] __might_sleep+0x3c/0x66 [] get_signal+0x9e/0xa70 [] do_notify_resume+0x6e/0x422 [] ret_from_exception+0x0/0x10 irq event stamp: 44512 hardirqs last enabled at (44511): [] _raw_spin_unlock_irqrestore+0x54/0x62 hardirqs last disabled at (44512): [] __trace_hardirqs_off+0xc/0x14 softirqs last enabled at (44472): [] __do_softirq+0x3de/0x51e softirqs last disabled at (44467): [] irq_exit+0xd6/0x104 ---[ end trace 0000000000000000 ]--- possible reason: unannotated irqs-on. Signed-off-by: Andrew Bresticker Fixes: 3c4697982982 ("riscv: Enable LOCKDEP_SUPPORT & fixup TRACE_IRQFLAGS_SUPPORT") Link: https://lore.kernel.org/r/20221111223108.1976562-1-abrestic@rivosinc.com Signed-off-by: Palmer Dabbelt

riscv: stacktrace: Make walk_stackframe cross pt_regs frame

2022-12-06T02:13:34Z

The current walk_stackframe with FRAME_POINTER would stop unwinding at ret_from_exception: BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:1518 in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 1, name: init CPU: 0 PID: 1 Comm: init Not tainted 5.10.113-00021-g15c15974895c-dirty #192 Call Trace: [] walk_stackframe+0x0/0xee [] show_stack+0x32/0x4a [] dump_stack_lvl+0x72/0x8e [] dump_stack+0x14/0x1c [] ___might_sleep+0x12e/0x138 [] __might_sleep+0x10/0x18 [] down_read+0x22/0xa4 [] do_page_fault+0xb0/0x2fe [] ret_from_exception+0x0/0xc The optimization would help walk_stackframe cross the pt_regs frame and get more backtrace of debug info: BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:1518 in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 1, name: init CPU: 0 PID: 1 Comm: init Not tainted 5.10.113-00021-g15c15974895c-dirty #192 Call Trace: [] walk_stackframe+0x0/0xee [] show_stack+0x32/0x4a [] dump_stack_lvl+0x72/0x8e [] dump_stack+0x14/0x1c [] ___might_sleep+0x12e/0x138 [] __might_sleep+0x10/0x18 [] down_read+0x22/0xa4 [] do_page_fault+0xb0/0x2fe [] ret_from_exception+0x0/0xc [] riscv_intc_irq+0x1a/0x72 [] ret_from_exception+0x0/0xc [] vma_link+0x54/0x160 [] mmap_region+0x2cc/0x4d0 [] do_mmap+0x2d8/0x3ac [] vm_mmap_pgoff+0x70/0xb8 [] vm_mmap+0x2a/0x36 [] elf_map+0x72/0x84 [] load_elf_binary+0x69a/0xec8 [] bprm_execve+0x246/0x53a [] kernel_execve+0xe8/0x124 [] run_init_process+0xfa/0x10c [] try_to_run_init_process+0x12/0x3c [] kernel_init+0xb4/0xf8 [] ret_from_exception+0x0/0xc Here is the error injection test code for the above output: drivers/irqchip/irq-riscv-intc.c: static asmlinkage void riscv_intc_irq(struct pt_regs *regs) { unsigned long cause = regs->cause & ~CAUSE_IRQ_FLAG; + u32 tmp; __get_user(tmp, (u32 *)0); Signed-off-by: Guo Ren Signed-off-by: Guo Ren Link: https://lore.kernel.org/r/20221109064937.3643993-3-guoren@kernel.org [Palmer: use SYM_CODE_*] Signed-off-by: Palmer Dabbelt

riscv: fix race when vmap stack overflow

2022-11-30T02:16:55Z

Currently, when detecting vmap stack overflow, riscv firstly switches to the so called shadow stack, then use this shadow stack to call the get_overflow_stack() to get the overflow stack. However, there's a race here if two or more harts use the same shadow stack at the same time. To solve this race, we introduce spin_shadow_stack atomic var, which will be swap between its own address and 0 in atomic way, when the var is set, it means the shadow_stack is being used; when the var is cleared, it means the shadow_stack isn't being used. Fixes: 31da94c25aea ("riscv: add VMAP_STACK overflow detection") Signed-off-by: Jisheng Zhang Suggested-by: Guo Ren Reviewed-by: Guo Ren Link: https://lore.kernel.org/r/20221030124517.2370-1-jszhang@kernel.org [Palmer: Add AQ to the swap, and also some comments.] Signed-off-by: Palmer Dabbelt

context_tracking: Split user tracking Kconfig

2022-06-30T00:04:09Z

Context tracking is going to be used not only to track user transitions but also idle/IRQs/NMIs. The user tracking part will then become a separate feature. Prepare Kconfig for that. [ frederic: Apply Max Filippov feedback. ] Signed-off-by: Frederic Weisbecker Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Neeraj Upadhyay Cc: Uladzislau Rezki Cc: Joel Fernandes Cc: Boqun Feng Cc: Nicolas Saenz Julienne Cc: Marcelo Tosatti Cc: Xiongfeng Wang Cc: Yu Liao Cc: Phil Auld Cc: Paul Gortmaker Cc: Alex Belits Signed-off-by: Paul E. McKenney Reviewed-by: Nicolas Saenz Julienne Tested-by: Nicolas Saenz Julienne

context_tracking: Rename context_tracking_user_enter/exit() to user_enter/exit_callable()

2022-06-30T00:03:27Z

context_tracking_user_enter() and context_tracking_user_exit() are ASM callable versions of user_enter() and user_exit() for architectures that didn't manage to check the context tracking static key from ASM. Change those function names to better reflect their purpose. [ frederic: Apply Max Filippov feedback. ] Signed-off-by: Frederic Weisbecker Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Neeraj Upadhyay Cc: Uladzislau Rezki Cc: Joel Fernandes Cc: Boqun Feng Cc: Nicolas Saenz Julienne Cc: Marcelo Tosatti Cc: Xiongfeng Wang Cc: Yu Liao Cc: Phil Auld Cc: Paul Gortmaker Cc: Alex Belits Signed-off-by: Paul E. McKenney Reviewed-by: Nicolas Saenz Julienne Tested-by: Nicolas Saenz Julienne