From 95485fdc64b1067e0e88d8c7980eb57994ad450e Mon Sep 17 00:00:00 2001 From: Yang Shi Date: Fri, 18 Sep 2015 22:09:00 +0100 Subject: [PATCH 1/5] arm64: debug: Fix typo in debug-monitors.c Fix comment typo: s/handers/handlers/ Signed-off-by: Yang Shi Signed-off-by: Will Deacon --- arch/arm64/kernel/debug-monitors.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c index cebf78661a55..8eef30f92651 100644 --- a/arch/arm64/kernel/debug-monitors.c +++ b/arch/arm64/kernel/debug-monitors.c @@ -201,7 +201,7 @@ void unregister_step_hook(struct step_hook *hook) } /* - * Call registered single step handers + * Call registered single step handlers * There is no Syndrome info to check for determining the handler. * So we call all the registered handlers, until the right handler is * found which returns zero. From 569ba74a7ba69f46ce2950bf085b37fea2408385 Mon Sep 17 00:00:00 2001 From: Mark Salyzyn Date: Mon, 21 Sep 2015 21:39:50 +0100 Subject: [PATCH 2/5] arm64: readahead: fault retry breaks mmap file read random detection This is the arm64 portion of commit 45cac65b0fcd ("readahead: fault retry breaks mmap file read random detection"), which was absent from the initial port and has since gone unnoticed. The original commit says: > .fault now can retry. The retry can break state machine of .fault. In > filemap_fault, if page is miss, ra->mmap_miss is increased. In the second > try, since the page is in page cache now, ra->mmap_miss is decreased. And > these are done in one fault, so we can't detect random mmap file access. > > Add a new flag to indicate .fault is tried once. In the second try, skip > ra->mmap_miss decreasing. The filemap_fault state machine is ok with it. With this change, Mark reports that: > Random read improves by 250%, sequential read improves by 40%, and > random write by 400% to an eMMC device with dm crypto wrapped around it. Cc: Shaohua Li Cc: Rik van Riel Cc: Wu Fengguang Cc: Signed-off-by: Mark Salyzyn Signed-off-by: Riley Andrews Signed-off-by: Will Deacon --- arch/arm64/mm/fault.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index aba9ead1384c..9fadf6d7039b 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -287,6 +287,7 @@ retry: * starvation. */ mm_flags &= ~FAULT_FLAG_ALLOW_RETRY; + mm_flags |= FAULT_FLAG_TRIED; goto retry; } } From abffa6f3b1578d5991545f6998ca7ee70b830e94 Mon Sep 17 00:00:00 2001 From: Yang Shi Date: Wed, 30 Sep 2015 19:23:12 +0100 Subject: [PATCH 3/5] arm64: convert patch_lock to raw lock When running kprobe test on arm64 rt kernel, it reports the below warning: root@qemu7:~# modprobe kprobe_example BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:917 in_atomic(): 0, irqs_disabled(): 128, pid: 484, name: modprobe CPU: 0 PID: 484 Comm: modprobe Not tainted 4.1.6-rt5 #2 Hardware name: linux,dummy-virt (DT) Call trace: [] dump_backtrace+0x0/0x128 [] show_stack+0x20/0x30 [] dump_stack+0x1c/0x28 [] ___might_sleep+0x120/0x198 [] rt_spin_lock+0x28/0x40 [] __aarch64_insn_write+0x28/0x78 [] aarch64_insn_patch_text_nosync+0x18/0x48 [] aarch64_insn_patch_text_cb+0x70/0xa0 [] aarch64_insn_patch_text_sync+0x28/0x48 [] arch_arm_kprobe+0x38/0x48 [] arm_kprobe+0x34/0x50 [] register_kprobe+0x4cc/0x5b8 [] kprobe_init+0x38/0x7c [kprobe_example] [] do_one_initcall+0x90/0x1b0 [] do_init_module+0x6c/0x1cc [] load_module+0x17f8/0x1db0 [] SyS_finit_module+0xb4/0xc8 Convert patch_lock to raw loc kto avoid this issue. Although the problem is found on rt kernel, the fix should be applicable to mainline kernel too. Acked-by: Steven Rostedt Signed-off-by: Yang Shi Signed-off-by: Will Deacon --- arch/arm64/kernel/insn.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c index f341866aa810..c08b9ad6f429 100644 --- a/arch/arm64/kernel/insn.c +++ b/arch/arm64/kernel/insn.c @@ -85,7 +85,7 @@ bool aarch64_insn_is_branch_imm(u32 insn) aarch64_insn_is_bcond(insn)); } -static DEFINE_SPINLOCK(patch_lock); +static DEFINE_RAW_SPINLOCK(patch_lock); static void __kprobes *patch_map(void *addr, int fixmap) { @@ -131,13 +131,13 @@ static int __kprobes __aarch64_insn_write(void *addr, u32 insn) unsigned long flags = 0; int ret; - spin_lock_irqsave(&patch_lock, flags); + raw_spin_lock_irqsave(&patch_lock, flags); waddr = patch_map(addr, FIX_TEXT_POKE0); ret = probe_kernel_write(waddr, &insn, AARCH64_INSN_SIZE); patch_unmap(FIX_TEXT_POKE0); - spin_unlock_irqrestore(&patch_lock, flags); + raw_spin_unlock_irqrestore(&patch_lock, flags); return ret; } From 4ca3bc86bea23f38596ce7508f75e072839bde44 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Tue, 6 Oct 2015 18:24:37 +0100 Subject: [PATCH 4/5] arm64: Don't relocate non-existent initrd When booting a kernel without an initrd, the kernel reports that it moves -1 bytes worth, having gone through the motions with initrd_start equal to initrd_end: Moving initrd from [4080000000-407fffffff] to [9fff49000-9fff48fff] Prevent this by bailing out early when the initrd size is zero (i.e. we have no initrd), avoiding the confusing message and other associated work. Fixes: 1570f0d7ab425c1e ("arm64: support initrd outside kernel linear map") Cc: Mark Salter Signed-off-by: Mark Rutland Signed-off-by: Will Deacon --- arch/arm64/kernel/setup.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index 6bab21f84a9f..232247945b1c 100644 --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -364,6 +364,8 @@ static void __init relocate_initrd(void) to_free = ram_end - orig_start; size = orig_end - orig_start; + if (!size) + return; /* initrd needs to be relocated completely inside linear mapping */ new_start = memblock_find_in_range(0, PFN_PHYS(max_pfn), From 62c6c61adbc623cdacf74b8f29c278e539060c48 Mon Sep 17 00:00:00 2001 From: Yang Shi Date: Mon, 5 Oct 2015 14:32:51 -0700 Subject: [PATCH 5/5] arm64: replace read_lock to rcu lock in call_break_hook BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:917 in_atomic(): 0, irqs_disabled(): 128, pid: 342, name: perf 1 lock held by perf/342: #0: (break_hook_lock){+.+...}, at: [] call_break_hook+0x34/0xd0 irq event stamp: 62224 hardirqs last enabled at (62223): [] __call_rcu.constprop.59+0x104/0x270 hardirqs last disabled at (62224): [] vprintk_emit+0x68/0x640 softirqs last enabled at (0): [] copy_process.part.8+0x428/0x17f8 softirqs last disabled at (0): [< (null)>] (null) CPU: 0 PID: 342 Comm: perf Not tainted 4.1.6-rt5 #4 Hardware name: linux,dummy-virt (DT) Call trace: [] dump_backtrace+0x0/0x128 [] show_stack+0x20/0x30 [] dump_stack+0x7c/0xa0 [] ___might_sleep+0x174/0x260 [] __rt_spin_lock+0x28/0x40 [] rt_read_lock+0x60/0x80 [] call_break_hook+0x30/0xd0 [] brk_handler+0x30/0x98 [] do_debug_exception+0x50/0xb8 Exception stack(0xffffffc00514fe30 to 0xffffffc00514ff50) fe20: 00000000 00000000 c1594680 0000007f fe40: ffffffff ffffffff 92063940 0000007f 0550dcd8 ffffffc0 00000000 00000000 fe60: 0514fe70 ffffffc0 000be1f8 ffffffc0 0514feb0 ffffffc0 0008948c ffffffc0 fe80: 00000004 00000000 0514fed0 ffffffc0 ffffffff ffffffff 9282a948 0000007f fea0: 00000000 00000000 9282b708 0000007f c1592820 0000007f 00083914 ffffffc0 fec0: 00000000 00000000 00000010 00000000 00000064 00000000 00000001 00000000 fee0: 005101e0 00000000 c1594680 0000007f c1594740 0000007f ffffffd8 ffffff80 ff00: 00000000 00000000 00000000 00000000 c1594770 0000007f c1594770 0000007f ff20: 00665e10 00000000 7f7f7f7f 7f7f7f7f 01010101 01010101 00000000 00000000 ff40: 928e4cc0 0000007f 91ff11e8 0000007f call_break_hook is called in atomic context (hard irq disabled), so replace the sleepable lock to rcu lock, replace relevant list operations to rcu version and call synchronize_rcu() in unregister_break_hook(). And, replace write lock to spinlock in {un}register_break_hook. Signed-off-by: Yang Shi Signed-off-by: Will Deacon --- arch/arm64/kernel/debug-monitors.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c index 8eef30f92651..253021ef2769 100644 --- a/arch/arm64/kernel/debug-monitors.c +++ b/arch/arm64/kernel/debug-monitors.c @@ -271,20 +271,21 @@ static int single_step_handler(unsigned long addr, unsigned int esr, * Use reader/writer locks instead of plain spinlock. */ static LIST_HEAD(break_hook); -static DEFINE_RWLOCK(break_hook_lock); +static DEFINE_SPINLOCK(break_hook_lock); void register_break_hook(struct break_hook *hook) { - write_lock(&break_hook_lock); - list_add(&hook->node, &break_hook); - write_unlock(&break_hook_lock); + spin_lock(&break_hook_lock); + list_add_rcu(&hook->node, &break_hook); + spin_unlock(&break_hook_lock); } void unregister_break_hook(struct break_hook *hook) { - write_lock(&break_hook_lock); - list_del(&hook->node); - write_unlock(&break_hook_lock); + spin_lock(&break_hook_lock); + list_del_rcu(&hook->node); + spin_unlock(&break_hook_lock); + synchronize_rcu(); } static int call_break_hook(struct pt_regs *regs, unsigned int esr) @@ -292,11 +293,11 @@ static int call_break_hook(struct pt_regs *regs, unsigned int esr) struct break_hook *hook; int (*fn)(struct pt_regs *regs, unsigned int esr) = NULL; - read_lock(&break_hook_lock); - list_for_each_entry(hook, &break_hook, node) + rcu_read_lock(); + list_for_each_entry_rcu(hook, &break_hook, node) if ((esr & hook->esr_mask) == hook->esr_val) fn = hook->fn; - read_unlock(&break_hook_lock); + rcu_read_unlock(); return fn ? fn(regs, esr) : DBG_HOOK_ERROR; }