From mboxrd@z Thu Jan 1 00:00:00 1970 From: tixy@yxit.co.uk (Tixy) Date: Tue, 22 Nov 2011 09:13:23 +0000 Subject: [PATCH 4/4] [RFC] Use generic ARM instruction set condition code checks for kprobes. In-Reply-To: <20111121183104.28964.87120.stgit@localhost6.localdomain6> References: <20111121183046.28964.23829.stgit@localhost6.localdomain6> <20111121183104.28964.87120.stgit@localhost6.localdomain6> Message-ID: <1321953203.2557.55.camel@computer2> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, 2011-11-21 at 18:31 +0000, Leif Lindholm wrote: > This patch changes the kprobes implementation to use the generic ARM > instruction set condition code checks, rather than a dedicated > implementation. > > Note, this is a direct interface change, and the resulting code is not > the prettiest, but this is an RFC only. It might be prettier to keep test_check_cc() but defined like: inline unsigned long test_check_cc(int cc, unsigned long cpsr) { return arm_check_condition(cc << 28, cpsr); } But still change to directly calling arm_check_condition() in the case of checking ARM instructions. > This code builds and links, but current 3.2-rc2 does not boot on my > Versatile Express board with CONFIG_ARM_KPROBES_TEST enabled either > with or without this patch. What are the symptoms? Have you tried setting VERBOSE to '1' at the top of kprobes-test.h? Currently the test code has problems building for Thumb, there's a patch: http://www.mail-archive.com/linaro-dev at lists.linaro.org/msg07925.html Also, when the test module is built-in, the tests fail near the beginning due to an issue with Thumb symbol handling in the kernel, see http://www.spinics.net/lists/arm-kernel/msg138283.html But building it as a module and insmod'ing should work. -- Tixy > Cc: Tixy > Signed-off-by: Leif Lindholm > --- > arch/arm/kernel/kprobes-test.c | 71 +++------------------------------------- > 1 files changed, 5 insertions(+), 66 deletions(-) > > diff --git a/arch/arm/kernel/kprobes-test.c b/arch/arm/kernel/kprobes-test.c > index e17cdd6..6f5328a 100644 > --- a/arch/arm/kernel/kprobes-test.c > +++ b/arch/arm/kernel/kprobes-test.c > @@ -202,6 +202,8 @@ > #include > #include > > +#include > + > #include "kprobes.h" > #include "kprobes-test.h" > > @@ -1048,69 +1050,6 @@ static int test_instance; > */ > #define PSR_IGNORE_BITS (PSR_A_BIT | PSR_F_BIT) > > -static unsigned long test_check_cc(int cc, unsigned long cpsr) > -{ > - unsigned long temp; > - > - switch (cc) { > - case 0x0: /* eq */ > - return cpsr & PSR_Z_BIT; > - > - case 0x1: /* ne */ > - return (~cpsr) & PSR_Z_BIT; > - > - case 0x2: /* cs */ > - return cpsr & PSR_C_BIT; > - > - case 0x3: /* cc */ > - return (~cpsr) & PSR_C_BIT; > - > - case 0x4: /* mi */ > - return cpsr & PSR_N_BIT; > - > - case 0x5: /* pl */ > - return (~cpsr) & PSR_N_BIT; > - > - case 0x6: /* vs */ > - return cpsr & PSR_V_BIT; > - > - case 0x7: /* vc */ > - return (~cpsr) & PSR_V_BIT; > - > - case 0x8: /* hi */ > - cpsr &= ~(cpsr >> 1); /* PSR_C_BIT &= ~PSR_Z_BIT */ > - return cpsr & PSR_C_BIT; > - > - case 0x9: /* ls */ > - cpsr &= ~(cpsr >> 1); /* PSR_C_BIT &= ~PSR_Z_BIT */ > - return (~cpsr) & PSR_C_BIT; > - > - case 0xa: /* ge */ > - cpsr ^= (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */ > - return (~cpsr) & PSR_N_BIT; > - > - case 0xb: /* lt */ > - cpsr ^= (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */ > - return cpsr & PSR_N_BIT; > - > - case 0xc: /* gt */ > - temp = cpsr ^ (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */ > - temp |= (cpsr << 1); /* PSR_N_BIT |= PSR_Z_BIT */ > - return (~temp) & PSR_N_BIT; > - > - case 0xd: /* le */ > - temp = cpsr ^ (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */ > - temp |= (cpsr << 1); /* PSR_N_BIT |= PSR_Z_BIT */ > - return temp & PSR_N_BIT; > - > - case 0xe: /* al */ > - case 0xf: /* unconditional */ > - return true; > - } > - BUG(); > - return false; > -} > - > static int is_last_scenario; > static int probe_should_run; /* 0 = no, 1 = yes, -1 = unknown */ > static int memory_needs_checking; > @@ -1128,7 +1067,7 @@ static unsigned long test_context_cpsr(int scenario) > > if (!test_case_is_thumb) { > /* Testing ARM code */ > - probe_should_run = test_check_cc(current_instruction >> 28, cpsr) != 0; > + probe_should_run = arm_check_condition(current_instruction, cpsr) != 0; > if (scenario == 15) > is_last_scenario = true; > > @@ -1136,7 +1075,7 @@ static unsigned long test_context_cpsr(int scenario) > /* Testing Thumb code without setting ITSTATE */ > if (kprobe_test_cc_position) { > int cc = (current_instruction >> kprobe_test_cc_position) & 0xf; > - probe_should_run = test_check_cc(cc, cpsr) != 0; > + probe_should_run = arm_check_condition(cc << 28, cpsr) != 0; > } > > if (scenario == 15) > @@ -1163,7 +1102,7 @@ static unsigned long test_context_cpsr(int scenario) > cpsr |= (mask & 0x8) << 23; /* ITSTATE<1> */ > cpsr |= (mask & 0x10) << 21; /* ITSTATE<0> */ > > - probe_should_run = test_check_cc((cpsr >> 12) & 0xf, cpsr) != 0; > + probe_should_run = arm_check_condition(((cpsr >> 12) & 0xf) << 28, cpsr) != 0; > > } else { > /* Testing Thumb code with several combinations of ITSTATE */ > >