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authorLinus Torvalds <[email protected]>2023-11-03 10:07:39 -1000
committerLinus Torvalds <[email protected]>2023-11-03 10:07:39 -1000
commit707df298cbde200b939c70be2577b20775fe3345 (patch)
treeb29f663dac88ac45d4f1d1465133c85439febe6c /arch/powerpc/lib/code-patching.c
parent6bdfe2d88b9ff8b0cce32ce87cd47c0e9d665f48 (diff)
parent303d77a6e1707498f09c9d8ee91b1dc07ca315a5 (diff)
Merge tag 'powerpc-6.7-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman: - Add support for KVM running as a nested hypervisor under development versions of PowerVM, using the new PAPR nested virtualisation API - Add support for the BPF prog pack allocator - A rework of the non-server MMU handling to support execute-only on all platforms - Some optimisations & cleanups for the powerpc qspinlock code - Various other small features and fixes Thanks to Aboorva Devarajan, Aditya Gupta, Amit Machhiwal, Benjamin Gray, Christophe Leroy, Dr. David Alan Gilbert, Gaurav Batra, Gautam Menghani, Geert Uytterhoeven, Haren Myneni, Hari Bathini, Joel Stanley, Jordan Niethe, Julia Lawall, Kautuk Consul, Kuan-Wei Chiu, Michael Neuling, Minjie Du, Muhammad Muzammil, Naveen N Rao, Nicholas Piggin, Nick Child, Nysal Jan K.A, Peter Lafreniere, Rob Herring, Sachin Sant, Sebastian Andrzej Siewior, Shrikanth Hegde, Srikar Dronamraju, Stanislav Kinsburskii, Vaibhav Jain, Wang Yufen, Yang Yingliang, and Yuan Tan. * tag 'powerpc-6.7-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (100 commits) powerpc/vmcore: Add MMU information to vmcoreinfo Revert "powerpc: add `cur_cpu_spec` symbol to vmcoreinfo" powerpc/bpf: use bpf_jit_binary_pack_[alloc|finalize|free] powerpc/bpf: rename powerpc64_jit_data to powerpc_jit_data powerpc/bpf: implement bpf_arch_text_invalidate for bpf_prog_pack powerpc/bpf: implement bpf_arch_text_copy powerpc/code-patching: introduce patch_instructions() powerpc/32s: Implement local_flush_tlb_page_psize() powerpc/pseries: use kfree_sensitive() in plpks_gen_password() powerpc/code-patching: Perform hwsync in __patch_instruction() in case of failure powerpc/fsl_msi: Use device_get_match_data() powerpc: Remove cpm_dp...() macros powerpc/qspinlock: Rename yield_propagate_owner tunable powerpc/qspinlock: Propagate sleepy if previous waiter is preempted powerpc/qspinlock: don't propagate the not-sleepy state powerpc/qspinlock: propagate owner preemptedness rather than CPU number powerpc/qspinlock: stop queued waiters trying to set lock sleepy powerpc/perf: Fix disabling BHRB and instruction sampling powerpc/trace: Add support for HAVE_FUNCTION_ARG_ACCESS_API powerpc/tools: Pass -mabi=elfv2 to gcc-check-mprofile-kernel.sh ...
Diffstat (limited to 'arch/powerpc/lib/code-patching.c')
-rw-r--r--arch/powerpc/lib/code-patching.c146
1 files changed, 139 insertions, 7 deletions
diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index b00112d7ad46..c6ab46156cda 100644
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -38,6 +38,7 @@ static int __patch_instruction(u32 *exec_addr, ppc_inst_t instr, u32 *patch_addr
return 0;
failed:
+ mb(); /* sync */
return -EPERM;
}
@@ -204,9 +205,6 @@ void __init poking_init(void)
{
int ret;
- if (!IS_ENABLED(CONFIG_STRICT_KERNEL_RWX))
- return;
-
if (mm_patch_enabled())
ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN,
"powerpc/text_poke_mm:online",
@@ -309,10 +307,6 @@ static int __do_patch_instruction_mm(u32 *addr, ppc_inst_t instr)
err = __patch_instruction(addr, instr, patch_addr);
- /* hwsync performed by __patch_instruction (sync) if successful */
- if (err)
- mb(); /* sync */
-
/* context synchronisation performed by __patch_instruction (isync or exception) */
stop_using_temp_mm(patching_mm, orig_mm);
@@ -378,6 +372,144 @@ int patch_instruction(u32 *addr, ppc_inst_t instr)
}
NOKPROBE_SYMBOL(patch_instruction);
+static int __patch_instructions(u32 *patch_addr, u32 *code, size_t len, bool repeat_instr)
+{
+ unsigned long start = (unsigned long)patch_addr;
+
+ /* Repeat instruction */
+ if (repeat_instr) {
+ ppc_inst_t instr = ppc_inst_read(code);
+
+ if (ppc_inst_prefixed(instr)) {
+ u64 val = ppc_inst_as_ulong(instr);
+
+ memset64((u64 *)patch_addr, val, len / 8);
+ } else {
+ u32 val = ppc_inst_val(instr);
+
+ memset32(patch_addr, val, len / 4);
+ }
+ } else {
+ memcpy(patch_addr, code, len);
+ }
+
+ smp_wmb(); /* smp write barrier */
+ flush_icache_range(start, start + len);
+ return 0;
+}
+
+/*
+ * A page is mapped and instructions that fit the page are patched.
+ * Assumes 'len' to be (PAGE_SIZE - offset_in_page(addr)) or below.
+ */
+static int __do_patch_instructions_mm(u32 *addr, u32 *code, size_t len, bool repeat_instr)
+{
+ struct mm_struct *patching_mm, *orig_mm;
+ unsigned long pfn = get_patch_pfn(addr);
+ unsigned long text_poke_addr;
+ spinlock_t *ptl;
+ u32 *patch_addr;
+ pte_t *pte;
+ int err;
+
+ patching_mm = __this_cpu_read(cpu_patching_context.mm);
+ text_poke_addr = __this_cpu_read(cpu_patching_context.addr);
+ patch_addr = (u32 *)(text_poke_addr + offset_in_page(addr));
+
+ pte = get_locked_pte(patching_mm, text_poke_addr, &ptl);
+ if (!pte)
+ return -ENOMEM;
+
+ __set_pte_at(patching_mm, text_poke_addr, pte, pfn_pte(pfn, PAGE_KERNEL), 0);
+
+ /* order PTE update before use, also serves as the hwsync */
+ asm volatile("ptesync" ::: "memory");
+
+ /* order context switch after arbitrary prior code */
+ isync();
+
+ orig_mm = start_using_temp_mm(patching_mm);
+
+ err = __patch_instructions(patch_addr, code, len, repeat_instr);
+
+ /* context synchronisation performed by __patch_instructions */
+ stop_using_temp_mm(patching_mm, orig_mm);
+
+ pte_clear(patching_mm, text_poke_addr, pte);
+ /*
+ * ptesync to order PTE update before TLB invalidation done
+ * by radix__local_flush_tlb_page_psize (in _tlbiel_va)
+ */
+ local_flush_tlb_page_psize(patching_mm, text_poke_addr, mmu_virtual_psize);
+
+ pte_unmap_unlock(pte, ptl);
+
+ return err;
+}
+
+/*
+ * A page is mapped and instructions that fit the page are patched.
+ * Assumes 'len' to be (PAGE_SIZE - offset_in_page(addr)) or below.
+ */
+static int __do_patch_instructions(u32 *addr, u32 *code, size_t len, bool repeat_instr)
+{
+ unsigned long pfn = get_patch_pfn(addr);
+ unsigned long text_poke_addr;
+ u32 *patch_addr;
+ pte_t *pte;
+ int err;
+
+ text_poke_addr = (unsigned long)__this_cpu_read(cpu_patching_context.addr) & PAGE_MASK;
+ patch_addr = (u32 *)(text_poke_addr + offset_in_page(addr));
+
+ pte = __this_cpu_read(cpu_patching_context.pte);
+ __set_pte_at(&init_mm, text_poke_addr, pte, pfn_pte(pfn, PAGE_KERNEL), 0);
+ /* See ptesync comment in radix__set_pte_at() */
+ if (radix_enabled())
+ asm volatile("ptesync" ::: "memory");
+
+ err = __patch_instructions(patch_addr, code, len, repeat_instr);
+
+ pte_clear(&init_mm, text_poke_addr, pte);
+ flush_tlb_kernel_range(text_poke_addr, text_poke_addr + PAGE_SIZE);
+
+ return err;
+}
+
+/*
+ * Patch 'addr' with 'len' bytes of instructions from 'code'.
+ *
+ * If repeat_instr is true, the same instruction is filled for
+ * 'len' bytes.
+ */
+int patch_instructions(u32 *addr, u32 *code, size_t len, bool repeat_instr)
+{
+ while (len > 0) {
+ unsigned long flags;
+ size_t plen;
+ int err;
+
+ plen = min_t(size_t, PAGE_SIZE - offset_in_page(addr), len);
+
+ local_irq_save(flags);
+ if (mm_patch_enabled())
+ err = __do_patch_instructions_mm(addr, code, plen, repeat_instr);
+ else
+ err = __do_patch_instructions(addr, code, plen, repeat_instr);
+ local_irq_restore(flags);
+ if (err)
+ return err;
+
+ len -= plen;
+ addr = (u32 *)((unsigned long)addr + plen);
+ if (!repeat_instr)
+ code = (u32 *)((unsigned long)code + plen);
+ }
+
+ return 0;
+}
+NOKPROBE_SYMBOL(patch_instructions);
+
int patch_branch(u32 *addr, unsigned long target, int flags)
{
ppc_inst_t instr;