Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760530Ab2HKB3B (ORCPT ); Fri, 10 Aug 2012 21:29:01 -0400 Received: from devils.ext.ti.com ([198.47.26.153]:53622 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759468Ab2HKBZx (ORCPT ); Fri, 10 Aug 2012 21:25:53 -0400 From: Cyril Chemparathy To: , CC: , , , , , , Cyril Chemparathy Subject: [PATCH v2 02/22] ARM: add self test for runtime patch mechanism Date: Fri, 10 Aug 2012 21:24:45 -0400 Message-ID: <1344648306-15619-3-git-send-email-cyril@ti.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1344648306-15619-1-git-send-email-cyril@ti.com> References: <1344648306-15619-1-git-send-email-cyril@ti.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3134 Lines: 100 This patch adds basic sanity tests to ensure that the instruction patching results in valid instruction encodings. This is done by verifying the output of the patch process against a vector of assembler generated instructions at init time. Signed-off-by: Cyril Chemparathy --- arch/arm/Kconfig | 12 ++++++++++++ arch/arm/kernel/runtime-patch.c | 41 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 53 insertions(+) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index d0a04ad..7e552dc 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -211,6 +211,18 @@ config ARM_PATCH_PHYS_VIRT this feature (eg, building a kernel for a single machine) and you need to shrink the kernel to the minimal size. +config ARM_RUNTIME_PATCH_TEST + bool "Self test runtime patching mechanism" if ARM_RUNTIME_PATCH + default y + help + Select this to enable init time self checking for the runtime kernel + patching mechanism. This enables an ISA specific set of tests that + ensure that the instructions generated by the patch process are + consistent with those generated by the assembler at compile time. + + Only disable this option if you need to shrink the kernel to the + minimal size. + config NEED_MACH_IO_H bool help diff --git a/arch/arm/kernel/runtime-patch.c b/arch/arm/kernel/runtime-patch.c index fd37a2b..c471d8c 100644 --- a/arch/arm/kernel/runtime-patch.c +++ b/arch/arm/kernel/runtime-patch.c @@ -163,6 +163,44 @@ static int apply_patch_imm8(const struct patch_info *p) return 0; } +#ifdef CONFIG_ARM_RUNTIME_PATCH_TEST +static void __init __used __naked __patch_test_code_imm8(void) +{ + __asm__ __volatile__ ( + " .irp shift1, 0, 6, 12, 18\n" + " .irp shift2, 0, 1, 2, 3, 4, 5\n" + " add r1, r2, #(0x41 << (\\shift1 + \\shift2))\n" + " .endr\n" + " .endr\n" + " .word 0\n" + : : : + ); +} + +static void __init test_patch_imm8(void) +{ + u32 test_code_addr = (u32)(&__patch_test_code_imm8); + u32 *test_code = (u32 *)(test_code_addr & ~0x3); + int i, ret; + u32 ninsn, insn; + + insn = test_code[0]; + for (i = 0; test_code[i]; i++) { + ret = do_patch_imm8(insn, 0x41 << i, &ninsn); + if (ret < 0) + pr_err("runtime patch (imm8): failed at shift %d\n", i); + else if (ninsn != test_code[i]) + pr_err("runtime patch (imm8): failed, need %x got %x\n", + test_code[i], ninsn); + } +} + +static void __init runtime_patch_test(void) +{ + test_patch_imm8(); +} +#endif + int runtime_patch(const void *table, unsigned size) { const struct patch_info *p = table, *end = (table + size); @@ -185,5 +223,8 @@ void __init runtime_patch_kernel(void) const void *start = &__runtime_patch_table_begin; const void *end = &__runtime_patch_table_end; +#ifdef CONFIG_ARM_RUNTIME_PATCH_TEST + runtime_patch_test(); +#endif BUG_ON(runtime_patch(start, end - start)); } -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/