From 034dd340b08be1f2f0477ad16131d609f9dbd53c Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 30 Aug 2026 09:22:00 -0700 Subject: Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Fix error output of boot instance creation failure Currently if a boot instance creation fails, instead of printing out the name of the instance that failed, it prints "(null)". That is because it prints "cur_str" that had already been processed by strsep(). Print the saved name instead. While at it, print the error code of the failure. - Fix use-after-free for same named historgrams Histograms can be named so that they can be used in multiple events. But if the named histogram has a variable attached, the second event that uses the named histogram which duplicates it and needs to free the original after duplication leaves the old variable in place and still visible. If another histogram uses than variable, it will use the stale one which will try to reference the freed duplicate histogram and crash the kernel. Free the duplicate variables along with the duplicated histogram data. - Check return value of kthread_run() in event self test The events self tests uses a kthread for testing but does not check if it succeeded in creating a kthread. If the kthread creation were to fail, the code will still try to call kthread_stop() on the error returned. - Fix race between reading trace_pipe and updating subbuffer size If a user is reading the trace_pipe file at the same time they update the ring buffer sub-buffer size, can cause the trace_pipe read to read stale data. Add trace_access_lock() around updating the ring buffer sub-buffer size. - Fix eventfs_inode on failure path in creation of the events directory In the creation of the "events" directory, if after allocating the eventfs_inode a failure is detected, it calls cleanup_ei() which calls free_ei(). The free_ei() will test if eventfs_inode being freed has no children. It is a bug if it does. But on the failure case of the creation of the "events" directory, the children lists have not yet been initialized and the free will trigger a warning because list_empty() on an uninitialized list returns false. Move the initialization into init_ei() where it makes more sense and makes sure that a created eventfs_inode has its lists initialized upon creation. - Check return value of kthread_run() in ftrace direct sample code The sample code that shows how to use the ftrace direct calls does not test the return of kthread_run() to see if it succeeds. Return a failure if the kthread_run() doesn't succeed. - Clear user events state on fork in case of alloc failure On fork, the child gets a pointer to the parent's user events state. It makes a copy of it then updates the child's pointer to it. But if the allocation fails, the duplication function leaves the child with a pointer to its parent's descriptor. When the child cleans up its data, it will free the parent's descriptor while the parent is still using it. In the duplication function, set the child's user_event_mm to NULL before testing if the allocation succeeded, and when it exits it will not free the parent's descriptor. - Fix retry exhaustion in simple ring buffer reader swap simple_ring_buffer_swap_reader_page() starts with retry set to 8 and post-decrements it only after a failed link replacement. On the final attempt, a successful replacement leaves retry at zero, while a failed replacement leaves it at -1. But the check for success expects the retry value to be non-zero and exits with an error on zero. This is the opposite result. Fix it. - Fail nicely when the remote swap_reader_page() returns an error Currently, if the swap_reader_page() of a remote buffer fails, it triggers a WARN_ON_ONCE() and continues normally. Instead, have it exit with an error and a pr_warn() print instead of a full WARNING. * tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: ring-buffer: Stop remote reader update when page swap fails tracing: Fix retry exhaustion in simple ring buffer reader swap tracing/user_events: Clear copied tracing state before fork duplication samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify eventfs: Initialize ei->children and ei->list in init_ei() tracing: Fix use-after-free in trace_pipe read on sub-buffer order change tracing: Fix crash passing ERR_PTR to kthread_stop() tracing: Fix use-after-free with same-name named triggers tracing: Fix logged instance name on creation failure --- arch/xtensa/lib/usercopy.S | 301 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 301 insertions(+) create mode 100644 arch/xtensa/lib/usercopy.S (limited to 'arch/xtensa/lib/usercopy.S') diff --git a/arch/xtensa/lib/usercopy.S b/arch/xtensa/lib/usercopy.S new file mode 100644 index 000000000..2c665c0b4 --- /dev/null +++ b/arch/xtensa/lib/usercopy.S @@ -0,0 +1,301 @@ +/* + * arch/xtensa/lib/usercopy.S + * + * Copy to/from user space (derived from arch/xtensa/lib/hal/memcopy.S) + * + * DO NOT COMBINE this function with . + * It needs to remain separate and distinct. The hal files are part + * of the Xtensa link-time HAL, and those files may differ per + * processor configuration. Patching the kernel for another + * processor configuration includes replacing the hal files, and we + * could lose the special functionality for accessing user-space + * memory during such a patch. We sacrifice a little code space here + * in favor to simplify code maintenance. + * + * This file is subject to the terms and conditions of the GNU General + * Public License. See the file "COPYING" in the main directory of + * this archive for more details. + * + * Copyright (C) 2002 Tensilica Inc. + */ + + +/* + * size_t __xtensa_copy_user (void *dst, const void *src, size_t len); + * + * The returned value is the number of bytes not copied. Implies zero + * is success. + * + * The general case algorithm is as follows: + * If the destination and source are both aligned, + * do 16B chunks with a loop, and then finish up with + * 8B, 4B, 2B, and 1B copies conditional on the length. + * If destination is aligned and source unaligned, + * do the same, but use SRC to align the source data. + * If destination is unaligned, align it by conditionally + * copying 1B and 2B and then retest. + * This code tries to use fall-through braches for the common + * case of aligned destinations (except for the branches to + * the alignment label). + * + * Register use: + * a0/ return address + * a1/ stack pointer + * a2/ return value + * a3/ src + * a4/ length + * a5/ dst + * a6/ tmp + * a7/ tmp + * a8/ tmp + * a9/ tmp + * a10/ tmp + * a11/ original length + */ + +#include +#include +#include + + .text +ENTRY(__xtensa_copy_user) + +#if !XCHAL_HAVE_LOOPS && defined(__XTENSA_CALL0_ABI__) +#define STACK_SIZE 4 +#else +#define STACK_SIZE 0 +#endif + abi_entry(STACK_SIZE) + # a2/ dst, a3/ src, a4/ len + mov a5, a2 # copy dst so that a2 is return value + mov a11, a4 # preserve original len for error case +.Lcommon: + bbsi.l a2, 0, .Ldst1mod2 # if dst is 1 mod 2 + bbsi.l a2, 1, .Ldst2mod4 # if dst is 2 mod 4 +.Ldstaligned: # return here from .Ldstunaligned when dst is aligned + srli a7, a4, 4 # number of loop iterations with 16B + # per iteration + movi a8, 3 # if source is also aligned, + bnone a3, a8, .Laligned # then use word copy + __ssa8 a3 # set shift amount from byte offset + bnez a4, .Lsrcunaligned + movi a2, 0 # return success for len==0 + abi_ret(STACK_SIZE) + +/* + * Destination is unaligned + */ + +.Ldst1mod2: # dst is only byte aligned + bltui a4, 7, .Lbytecopy # do short copies byte by byte + + # copy 1 byte +EX(10f) l8ui a6, a3, 0 + addi a3, a3, 1 +EX(10f) s8i a6, a5, 0 + addi a5, a5, 1 + addi a4, a4, -1 + bbci.l a5, 1, .Ldstaligned # if dst is now aligned, then + # return to main algorithm +.Ldst2mod4: # dst 16-bit aligned + # copy 2 bytes + bltui a4, 6, .Lbytecopy # do short copies byte by byte +EX(10f) l8ui a6, a3, 0 +EX(10f) l8ui a7, a3, 1 + addi a3, a3, 2 +EX(10f) s8i a6, a5, 0 +EX(10f) s8i a7, a5, 1 + addi a5, a5, 2 + addi a4, a4, -2 + j .Ldstaligned # dst is now aligned, return to main algorithm + +/* + * Byte by byte copy + */ + .align 4 + .byte 0 # 1 mod 4 alignment for LOOPNEZ + # (0 mod 4 alignment for LBEG) +.Lbytecopy: +#if XCHAL_HAVE_LOOPS + loopnez a4, .Lbytecopydone +#else /* !XCHAL_HAVE_LOOPS */ + beqz a4, .Lbytecopydone + add a7, a3, a4 # a7 = end address for source +#endif /* !XCHAL_HAVE_LOOPS */ +.Lnextbyte: +EX(10f) l8ui a6, a3, 0 + addi a3, a3, 1 +EX(10f) s8i a6, a5, 0 + addi a5, a5, 1 +#if !XCHAL_HAVE_LOOPS + blt a3, a7, .Lnextbyte +#endif /* !XCHAL_HAVE_LOOPS */ +.Lbytecopydone: + movi a2, 0 # return success for len bytes copied + abi_ret(STACK_SIZE) + +/* + * Destination and source are word-aligned. + */ + # copy 16 bytes per iteration for word-aligned dst and word-aligned src + .align 4 # 1 mod 4 alignment for LOOPNEZ + .byte 0 # (0 mod 4 alignment for LBEG) +.Laligned: +#if XCHAL_HAVE_LOOPS + loopnez a7, .Loop1done +#else /* !XCHAL_HAVE_LOOPS */ + beqz a7, .Loop1done + slli a8, a7, 4 + add a8, a8, a3 # a8 = end of last 16B source chunk +#endif /* !XCHAL_HAVE_LOOPS */ +.Loop1: +EX(10f) l32i a6, a3, 0 +EX(10f) l32i a7, a3, 4 +EX(10f) s32i a6, a5, 0 +EX(10f) l32i a6, a3, 8 +EX(10f) s32i a7, a5, 4 +EX(10f) l32i a7, a3, 12 +EX(10f) s32i a6, a5, 8 + addi a3, a3, 16 +EX(10f) s32i a7, a5, 12 + addi a5, a5, 16 +#if !XCHAL_HAVE_LOOPS + blt a3, a8, .Loop1 +#endif /* !XCHAL_HAVE_LOOPS */ +.Loop1done: + bbci.l a4, 3, .L2 + # copy 8 bytes +EX(10f) l32i a6, a3, 0 +EX(10f) l32i a7, a3, 4 + addi a3, a3, 8 +EX(10f) s32i a6, a5, 0 +EX(10f) s32i a7, a5, 4 + addi a5, a5, 8 +.L2: + bbci.l a4, 2, .L3 + # copy 4 bytes +EX(10f) l32i a6, a3, 0 + addi a3, a3, 4 +EX(10f) s32i a6, a5, 0 + addi a5, a5, 4 +.L3: + bbci.l a4, 1, .L4 + # copy 2 bytes +EX(10f) l16ui a6, a3, 0 + addi a3, a3, 2 +EX(10f) s16i a6, a5, 0 + addi a5, a5, 2 +.L4: + bbci.l a4, 0, .L5 + # copy 1 byte +EX(10f) l8ui a6, a3, 0 +EX(10f) s8i a6, a5, 0 +.L5: + movi a2, 0 # return success for len bytes copied + abi_ret(STACK_SIZE) + +/* + * Destination is aligned, Source is unaligned + */ + + .align 4 + .byte 0 # 1 mod 4 alignement for LOOPNEZ + # (0 mod 4 alignment for LBEG) +.Lsrcunaligned: + # copy 16 bytes per iteration for word-aligned dst and unaligned src + and a10, a3, a8 # save unalignment offset for below + sub a3, a3, a10 # align a3 (to avoid sim warnings only; not needed for hardware) +EX(10f) l32i a6, a3, 0 # load first word +#if XCHAL_HAVE_LOOPS + loopnez a7, .Loop2done +#else /* !XCHAL_HAVE_LOOPS */ + beqz a7, .Loop2done +#if defined(__XTENSA_CALL0_ABI__) + s32i a10, a1, 0 + slli a10, a7, 4 + add a10, a10, a3 # a10 = end of last 16B source chunk +#else + slli a12, a7, 4 + add a12, a12, a3 # a12 = end of last 16B source chunk +#endif +#endif /* !XCHAL_HAVE_LOOPS */ +.Loop2: +EX(10f) l32i a7, a3, 4 +EX(10f) l32i a8, a3, 8 + __src_b a6, a6, a7 +EX(10f) s32i a6, a5, 0 +EX(10f) l32i a9, a3, 12 + __src_b a7, a7, a8 +EX(10f) s32i a7, a5, 4 +EX(10f) l32i a6, a3, 16 + __src_b a8, a8, a9 +EX(10f) s32i a8, a5, 8 + addi a3, a3, 16 + __src_b a9, a9, a6 +EX(10f) s32i a9, a5, 12 + addi a5, a5, 16 +#if !XCHAL_HAVE_LOOPS +#if defined(__XTENSA_CALL0_ABI__) + blt a3, a10, .Loop2 + l32i a10, a1, 0 +#else + blt a3, a12, .Loop2 +#endif +#endif /* !XCHAL_HAVE_LOOPS */ +.Loop2done: + bbci.l a4, 3, .L12 + # copy 8 bytes +EX(10f) l32i a7, a3, 4 +EX(10f) l32i a8, a3, 8 + __src_b a6, a6, a7 +EX(10f) s32i a6, a5, 0 + addi a3, a3, 8 + __src_b a7, a7, a8 +EX(10f) s32i a7, a5, 4 + addi a5, a5, 8 + mov a6, a8 +.L12: + bbci.l a4, 2, .L13 + # copy 4 bytes +EX(10f) l32i a7, a3, 4 + addi a3, a3, 4 + __src_b a6, a6, a7 +EX(10f) s32i a6, a5, 0 + addi a5, a5, 4 + mov a6, a7 +.L13: + add a3, a3, a10 # readjust a3 with correct misalignment + bbci.l a4, 1, .L14 + # copy 2 bytes +EX(10f) l8ui a6, a3, 0 +EX(10f) l8ui a7, a3, 1 + addi a3, a3, 2 +EX(10f) s8i a6, a5, 0 +EX(10f) s8i a7, a5, 1 + addi a5, a5, 2 +.L14: + bbci.l a4, 0, .L15 + # copy 1 byte +EX(10f) l8ui a6, a3, 0 +EX(10f) s8i a6, a5, 0 +.L15: + movi a2, 0 # return success for len bytes copied + abi_ret(STACK_SIZE) + +ENDPROC(__xtensa_copy_user) +EXPORT_SYMBOL(__xtensa_copy_user) + + .section .fixup, "ax" + .align 4 + +/* a2 = original dst; a5 = current dst; a11= original len + * bytes_copied = a5 - a2 + * retval = bytes_not_copied = original len - bytes_copied + * retval = a11 - (a5 - a2) + */ + + +10: + sub a2, a5, a2 /* a2 <-- bytes copied */ + sub a2, a11, a2 /* a2 <-- bytes not copied */ + abi_ret(STACK_SIZE) -- cgit v1.3.1