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powerpc: Add tests of the code patching routines
Add tests of the existing code patching routines, as well as the new routines added in the last commit. The self-tests are run late in boot when CONFIG_CODE_PATCHING_SELFTEST=y, which depends on DEBUG_KERNEL=y. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Acked-by: Kumar Gala <galak@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
This commit is contained in:
Michael Ellerman
Paul Mackerras
parent
411781a290
commit
ae0dc73625
@ -57,6 +57,11 @@ config KGDB
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debugger. See <http://kgdb.sourceforge.net/> for more information.
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Unless you are intending to debug the kernel, say N here.
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config CODE_PATCHING_SELFTEST
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bool "Run self-tests of the code-patching code."
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depends on DEBUG_KERNEL
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default n
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choice
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prompt "Serial Port"
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depends on KGDB
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@ -8,6 +8,9 @@
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*/
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#include <linux/kernel.h>
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#include <linux/vmalloc.h>
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#include <linux/init.h>
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#include <asm/page.h>
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#include <asm/code-patching.h>
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@ -148,3 +151,298 @@ unsigned int translate_branch(const unsigned int *dest, const unsigned int *src)
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return 0;
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}
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#ifdef CONFIG_CODE_PATCHING_SELFTEST
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static void __init test_trampoline(void)
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{
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asm ("nop;\n");
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}
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#define check(x) \
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if (!(x)) printk("code-patching: test failed at line %d\n", __LINE__);
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static void __init test_branch_iform(void)
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{
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unsigned int instr;
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unsigned long addr;
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addr = (unsigned long)&instr;
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/* The simplest case, branch to self, no flags */
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check(instr_is_branch_iform(0x48000000));
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/* All bits of target set, and flags */
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check(instr_is_branch_iform(0x4bffffff));
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/* High bit of opcode set, which is wrong */
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check(!instr_is_branch_iform(0xcbffffff));
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/* Middle bits of opcode set, which is wrong */
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check(!instr_is_branch_iform(0x7bffffff));
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/* Simplest case, branch to self with link */
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check(instr_is_branch_iform(0x48000001));
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/* All bits of targets set */
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check(instr_is_branch_iform(0x4bfffffd));
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/* Some bits of targets set */
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check(instr_is_branch_iform(0x4bff00fd));
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/* Must be a valid branch to start with */
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check(!instr_is_branch_iform(0x7bfffffd));
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/* Absolute branch to 0x100 */
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instr = 0x48000103;
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check(instr_is_branch_to_addr(&instr, 0x100));
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/* Absolute branch to 0x420fc */
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instr = 0x480420ff;
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check(instr_is_branch_to_addr(&instr, 0x420fc));
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/* Maximum positive relative branch, + 20MB - 4B */
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instr = 0x49fffffc;
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check(instr_is_branch_to_addr(&instr, addr + 0x1FFFFFC));
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/* Smallest negative relative branch, - 4B */
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instr = 0x4bfffffc;
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check(instr_is_branch_to_addr(&instr, addr - 4));
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/* Largest negative relative branch, - 32 MB */
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instr = 0x4a000000;
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check(instr_is_branch_to_addr(&instr, addr - 0x2000000));
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/* Branch to self, with link */
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instr = create_branch(&instr, addr, BRANCH_SET_LINK);
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check(instr_is_branch_to_addr(&instr, addr));
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/* Branch to self - 0x100, with link */
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instr = create_branch(&instr, addr - 0x100, BRANCH_SET_LINK);
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check(instr_is_branch_to_addr(&instr, addr - 0x100));
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/* Branch to self + 0x100, no link */
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instr = create_branch(&instr, addr + 0x100, 0);
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check(instr_is_branch_to_addr(&instr, addr + 0x100));
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/* Maximum relative negative offset, - 32 MB */
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instr = create_branch(&instr, addr - 0x2000000, BRANCH_SET_LINK);
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check(instr_is_branch_to_addr(&instr, addr - 0x2000000));
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/* Out of range relative negative offset, - 32 MB + 4*/
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instr = create_branch(&instr, addr - 0x2000004, BRANCH_SET_LINK);
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check(instr == 0);
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/* Out of range relative positive offset, + 32 MB */
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instr = create_branch(&instr, addr + 0x2000000, BRANCH_SET_LINK);
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check(instr == 0);
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/* Unaligned target */
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instr = create_branch(&instr, addr + 3, BRANCH_SET_LINK);
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check(instr == 0);
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/* Check flags are masked correctly */
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instr = create_branch(&instr, addr, 0xFFFFFFFC);
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check(instr_is_branch_to_addr(&instr, addr));
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check(instr == 0x48000000);
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}
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static void __init test_create_function_call(void)
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{
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unsigned int *iptr;
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unsigned long dest;
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/* Check we can create a function call */
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iptr = (unsigned int *)ppc_function_entry(test_trampoline);
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dest = ppc_function_entry(test_create_function_call);
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patch_instruction(iptr, create_branch(iptr, dest, BRANCH_SET_LINK));
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check(instr_is_branch_to_addr(iptr, dest));
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}
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static void __init test_branch_bform(void)
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{
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unsigned long addr;
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unsigned int *iptr, instr, flags;
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iptr = &instr;
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addr = (unsigned long)iptr;
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/* The simplest case, branch to self, no flags */
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check(instr_is_branch_bform(0x40000000));
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/* All bits of target set, and flags */
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check(instr_is_branch_bform(0x43ffffff));
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/* High bit of opcode set, which is wrong */
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check(!instr_is_branch_bform(0xc3ffffff));
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/* Middle bits of opcode set, which is wrong */
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check(!instr_is_branch_bform(0x7bffffff));
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/* Absolute conditional branch to 0x100 */
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instr = 0x43ff0103;
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check(instr_is_branch_to_addr(&instr, 0x100));
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/* Absolute conditional branch to 0x20fc */
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instr = 0x43ff20ff;
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check(instr_is_branch_to_addr(&instr, 0x20fc));
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/* Maximum positive relative conditional branch, + 32 KB - 4B */
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instr = 0x43ff7ffc;
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check(instr_is_branch_to_addr(&instr, addr + 0x7FFC));
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/* Smallest negative relative conditional branch, - 4B */
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instr = 0x43fffffc;
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check(instr_is_branch_to_addr(&instr, addr - 4));
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/* Largest negative relative conditional branch, - 32 KB */
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instr = 0x43ff8000;
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check(instr_is_branch_to_addr(&instr, addr - 0x8000));
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/* All condition code bits set & link */
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flags = 0x3ff000 | BRANCH_SET_LINK;
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/* Branch to self */
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instr = create_cond_branch(iptr, addr, flags);
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check(instr_is_branch_to_addr(&instr, addr));
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/* Branch to self - 0x100 */
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instr = create_cond_branch(iptr, addr - 0x100, flags);
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check(instr_is_branch_to_addr(&instr, addr - 0x100));
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/* Branch to self + 0x100 */
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instr = create_cond_branch(iptr, addr + 0x100, flags);
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check(instr_is_branch_to_addr(&instr, addr + 0x100));
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/* Maximum relative negative offset, - 32 KB */
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instr = create_cond_branch(iptr, addr - 0x8000, flags);
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check(instr_is_branch_to_addr(&instr, addr - 0x8000));
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/* Out of range relative negative offset, - 32 KB + 4*/
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instr = create_cond_branch(iptr, addr - 0x8004, flags);
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check(instr == 0);
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/* Out of range relative positive offset, + 32 KB */
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instr = create_cond_branch(iptr, addr + 0x8000, flags);
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check(instr == 0);
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/* Unaligned target */
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instr = create_cond_branch(iptr, addr + 3, flags);
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check(instr == 0);
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/* Check flags are masked correctly */
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instr = create_cond_branch(iptr, addr, 0xFFFFFFFC);
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check(instr_is_branch_to_addr(&instr, addr));
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check(instr == 0x43FF0000);
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}
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static void __init test_translate_branch(void)
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{
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unsigned long addr;
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unsigned int *p, *q;
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void *buf;
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buf = vmalloc(PAGE_ALIGN(0x2000000 + 1));
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check(buf);
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if (!buf)
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return;
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/* Simple case, branch to self moved a little */
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p = buf;
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addr = (unsigned long)p;
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patch_branch(p, addr, 0);
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check(instr_is_branch_to_addr(p, addr));
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q = p + 1;
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patch_instruction(q, translate_branch(q, p));
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check(instr_is_branch_to_addr(q, addr));
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/* Maximum negative case, move b . to addr + 32 MB */
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p = buf;
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addr = (unsigned long)p;
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patch_branch(p, addr, 0);
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q = buf + 0x2000000;
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patch_instruction(q, translate_branch(q, p));
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check(instr_is_branch_to_addr(p, addr));
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check(instr_is_branch_to_addr(q, addr));
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check(*q == 0x4a000000);
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/* Maximum positive case, move x to x - 32 MB + 4 */
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p = buf + 0x2000000;
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addr = (unsigned long)p;
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patch_branch(p, addr, 0);
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q = buf + 4;
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patch_instruction(q, translate_branch(q, p));
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check(instr_is_branch_to_addr(p, addr));
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check(instr_is_branch_to_addr(q, addr));
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check(*q == 0x49fffffc);
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/* Jump to x + 16 MB moved to x + 20 MB */
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p = buf;
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addr = 0x1000000 + (unsigned long)buf;
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patch_branch(p, addr, BRANCH_SET_LINK);
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q = buf + 0x1400000;
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patch_instruction(q, translate_branch(q, p));
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check(instr_is_branch_to_addr(p, addr));
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check(instr_is_branch_to_addr(q, addr));
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/* Jump to x + 16 MB moved to x - 16 MB + 4 */
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p = buf + 0x1000000;
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addr = 0x2000000 + (unsigned long)buf;
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patch_branch(p, addr, 0);
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q = buf + 4;
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patch_instruction(q, translate_branch(q, p));
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check(instr_is_branch_to_addr(p, addr));
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check(instr_is_branch_to_addr(q, addr));
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/* Conditional branch tests */
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/* Simple case, branch to self moved a little */
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p = buf;
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addr = (unsigned long)p;
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patch_instruction(p, create_cond_branch(p, addr, 0));
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check(instr_is_branch_to_addr(p, addr));
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q = p + 1;
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patch_instruction(q, translate_branch(q, p));
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check(instr_is_branch_to_addr(q, addr));
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/* Maximum negative case, move b . to addr + 32 KB */
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p = buf;
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addr = (unsigned long)p;
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patch_instruction(p, create_cond_branch(p, addr, 0xFFFFFFFC));
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q = buf + 0x8000;
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patch_instruction(q, translate_branch(q, p));
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check(instr_is_branch_to_addr(p, addr));
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check(instr_is_branch_to_addr(q, addr));
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check(*q == 0x43ff8000);
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/* Maximum positive case, move x to x - 32 KB + 4 */
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p = buf + 0x8000;
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addr = (unsigned long)p;
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patch_instruction(p, create_cond_branch(p, addr, 0xFFFFFFFC));
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q = buf + 4;
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patch_instruction(q, translate_branch(q, p));
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check(instr_is_branch_to_addr(p, addr));
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check(instr_is_branch_to_addr(q, addr));
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check(*q == 0x43ff7ffc);
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/* Jump to x + 12 KB moved to x + 20 KB */
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p = buf;
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addr = 0x3000 + (unsigned long)buf;
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patch_instruction(p, create_cond_branch(p, addr, BRANCH_SET_LINK));
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q = buf + 0x5000;
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patch_instruction(q, translate_branch(q, p));
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check(instr_is_branch_to_addr(p, addr));
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check(instr_is_branch_to_addr(q, addr));
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/* Jump to x + 8 KB moved to x - 8 KB + 4 */
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p = buf + 0x2000;
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addr = 0x4000 + (unsigned long)buf;
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patch_instruction(p, create_cond_branch(p, addr, 0));
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q = buf + 4;
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patch_instruction(q, translate_branch(q, p));
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check(instr_is_branch_to_addr(p, addr));
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check(instr_is_branch_to_addr(q, addr));
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/* Free the buffer we were using */
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vfree(buf);
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}
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static int __init test_code_patching(void)
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{
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printk(KERN_DEBUG "Running code patching self-tests ...\n");
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test_branch_iform();
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test_branch_bform();
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test_create_function_call();
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test_translate_branch();
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return 0;
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}
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late_initcall(test_code_patching);
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#endif /* CONFIG_CODE_PATCHING_SELFTEST */
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