Re: [PATCH v2 07/12] powerpc/lib/code-patching: Don't use struct 'ppc_inst' for runnable code in tests.

'struct ppc_inst' is meant to represent an instruction internally, it
is not meant to dereference code in memory.

For testing code patching, use patch_instruction() to properly
write into memory the code to be tested.

Signed-off-by: Christophe Leroy <redacted>
---
 arch/powerpc/lib/code-patching.c | 95 ++++++++++++++++++--------------
 1 file changed, 53 insertions(+), 42 deletions(-)

diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index 82f2c1edb498..508e9511ca96 100644
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c

@@ -422,9 +422,9 @@ static void __init test_branch_iform(void)
 {
        int err;
        struct ppc_inst instr;
-       unsigned long addr;
-
-       addr = (unsigned long)&instr;
+       unsigned int tmp[2];
+       struct ppc_inst *iptr = (struct ppc_inst *)tmp;
+       unsigned long addr = (unsigned long)tmp;

        /* The simplest case, branch to self, no flags */
        check(instr_is_branch_iform(ppc_inst(0x48000000)));

@@ -445,52 +445,57 @@ static void __init test_branch_iform(void)
        check(!instr_is_branch_iform(ppc_inst(0x7bfffffd)));

        /* Absolute branch to 0x100 */
-       instr = ppc_inst(0x48000103);
-       check(instr_is_branch_to_addr(&instr, 0x100));
+       patch_instruction(iptr, ppc_inst(0x48000103));
+       check(instr_is_branch_to_addr(iptr, 0x100));
        /* Absolute branch to 0x420fc */
-       instr = ppc_inst(0x480420ff);
-       check(instr_is_branch_to_addr(&instr, 0x420fc));
+       patch_instruction(iptr, ppc_inst(0x480420ff));
+       check(instr_is_branch_to_addr(iptr, 0x420fc));
        /* Maximum positive relative branch, + 20MB - 4B */
-       instr = ppc_inst(0x49fffffc);
-       check(instr_is_branch_to_addr(&instr, addr + 0x1FFFFFC));
+       patch_instruction(iptr, ppc_inst(0x49fffffc));
+       check(instr_is_branch_to_addr(iptr, addr + 0x1FFFFFC));
        /* Smallest negative relative branch, - 4B */
-       instr = ppc_inst(0x4bfffffc);
-       check(instr_is_branch_to_addr(&instr, addr - 4));
+       patch_instruction(iptr, ppc_inst(0x4bfffffc));
+       check(instr_is_branch_to_addr(iptr, addr - 4));
        /* Largest negative relative branch, - 32 MB */
-       instr = ppc_inst(0x4a000000);
-       check(instr_is_branch_to_addr(&instr, addr - 0x2000000));
+       patch_instruction(iptr, ppc_inst(0x4a000000));
+       check(instr_is_branch_to_addr(iptr, addr - 0x2000000));

        /* Branch to self, with link */
-       err = create_branch(&instr, &instr, addr, BRANCH_SET_LINK);
-       check(instr_is_branch_to_addr(&instr, addr));
+       err = create_branch(&instr, iptr, addr, BRANCH_SET_LINK);
+       patch_instruction(iptr, instr);
+       check(instr_is_branch_to_addr(iptr, addr));

        /* Branch to self - 0x100, with link */
-       err = create_branch(&instr, &instr, addr - 0x100, BRANCH_SET_LINK);
-       check(instr_is_branch_to_addr(&instr, addr - 0x100));
+       err = create_branch(&instr, iptr, addr - 0x100, BRANCH_SET_LINK);
+       patch_instruction(iptr, instr);
+       check(instr_is_branch_to_addr(iptr, addr - 0x100));

        /* Branch to self + 0x100, no link */
-       err = create_branch(&instr, &instr, addr + 0x100, 0);
-       check(instr_is_branch_to_addr(&instr, addr + 0x100));
+       err = create_branch(&instr, iptr, addr + 0x100, 0);
+       patch_instruction(iptr, instr);
+       check(instr_is_branch_to_addr(iptr, addr + 0x100));

        /* Maximum relative negative offset, - 32 MB */
-       err = create_branch(&instr, &instr, addr - 0x2000000, BRANCH_SET_LINK);
-       check(instr_is_branch_to_addr(&instr, addr - 0x2000000));
+       err = create_branch(&instr, iptr, addr - 0x2000000, BRANCH_SET_LINK);
+       patch_instruction(iptr, instr);
+       check(instr_is_branch_to_addr(iptr, addr - 0x2000000));

        /* Out of range relative negative offset, - 32 MB + 4*/
-       err = create_branch(&instr, &instr, addr - 0x2000004, BRANCH_SET_LINK);
+       err = create_branch(&instr, iptr, addr - 0x2000004, BRANCH_SET_LINK);
        check(err);

        /* Out of range relative positive offset, + 32 MB */
-       err = create_branch(&instr, &instr, addr + 0x2000000, BRANCH_SET_LINK);
+       err = create_branch(&instr, iptr, addr + 0x2000000, BRANCH_SET_LINK);
        check(err);

        /* Unaligned target */
-       err = create_branch(&instr, &instr, addr + 3, BRANCH_SET_LINK);
+       err = create_branch(&instr, iptr, addr + 3, BRANCH_SET_LINK);
        check(err);

        /* Check flags are masked correctly */
-       err = create_branch(&instr, &instr, addr, 0xFFFFFFFC);
-       check(instr_is_branch_to_addr(&instr, addr));
+       err = create_branch(&instr, iptr, addr, 0xFFFFFFFC);
+       patch_instruction(iptr, instr);
+       check(instr_is_branch_to_addr(iptr, addr));
        check(ppc_inst_equal(instr, ppc_inst(0x48000000)));
 }

@@ -513,9 +518,10 @@ static void __init test_branch_bform(void)
        int err;
        unsigned long addr;
        struct ppc_inst *iptr, instr;
+       unsigned int tmp[2];
        unsigned int flags;

-       iptr = &instr;
+       iptr = (struct ppc_inst *)tmp;
        addr = (unsigned long)iptr;

        /* The simplest case, branch to self, no flags */

@@ -528,39 +534,43 @@ static void __init test_branch_bform(void)
        check(!instr_is_branch_bform(ppc_inst(0x7bffffff)));

        /* Absolute conditional branch to 0x100 */
-       instr = ppc_inst(0x43ff0103);
-       check(instr_is_branch_to_addr(&instr, 0x100));
+       patch_instruction(iptr, ppc_inst(0x43ff0103));
+       check(instr_is_branch_to_addr(iptr, 0x100));
        /* Absolute conditional branch to 0x20fc */
-       instr = ppc_inst(0x43ff20ff);
-       check(instr_is_branch_to_addr(&instr, 0x20fc));
+       patch_instruction(iptr, ppc_inst(0x43ff20ff));
+       check(instr_is_branch_to_addr(iptr, 0x20fc));
        /* Maximum positive relative conditional branch, + 32 KB - 4B */
-       instr = ppc_inst(0x43ff7ffc);
-       check(instr_is_branch_to_addr(&instr, addr + 0x7FFC));
+       patch_instruction(iptr, ppc_inst(0x43ff7ffc));
+       check(instr_is_branch_to_addr(iptr, addr + 0x7FFC));
        /* Smallest negative relative conditional branch, - 4B */
-       instr = ppc_inst(0x43fffffc);
-       check(instr_is_branch_to_addr(&instr, addr - 4));
+       patch_instruction(iptr, ppc_inst(0x43fffffc));
+       check(instr_is_branch_to_addr(iptr, addr - 4));
        /* Largest negative relative conditional branch, - 32 KB */
-       instr = ppc_inst(0x43ff8000);
-       check(instr_is_branch_to_addr(&instr, addr - 0x8000));
+       patch_instruction(iptr, ppc_inst(0x43ff8000));
+       check(instr_is_branch_to_addr(iptr, addr - 0x8000));

        /* All condition code bits set & link */
        flags = 0x3ff000 | BRANCH_SET_LINK;

        /* Branch to self */
        err = create_cond_branch(&instr, iptr, addr, flags);
-       check(instr_is_branch_to_addr(&instr, addr));
+       patch_instruction(iptr, instr);
+       check(instr_is_branch_to_addr(iptr, addr));

        /* Branch to self - 0x100 */
        err = create_cond_branch(&instr, iptr, addr - 0x100, flags);
-       check(instr_is_branch_to_addr(&instr, addr - 0x100));
+       patch_instruction(iptr, instr);
+       check(instr_is_branch_to_addr(iptr, addr - 0x100));

        /* Branch to self + 0x100 */
        err = create_cond_branch(&instr, iptr, addr + 0x100, flags);
-       check(instr_is_branch_to_addr(&instr, addr + 0x100));
+       patch_instruction(iptr, instr);
+       check(instr_is_branch_to_addr(iptr, addr + 0x100));

        /* Maximum relative negative offset, - 32 KB */
        err = create_cond_branch(&instr, iptr, addr - 0x8000, flags);
-       check(instr_is_branch_to_addr(&instr, addr - 0x8000));
+       patch_instruction(iptr, instr);
+       check(instr_is_branch_to_addr(iptr, addr - 0x8000));

        /* Out of range relative negative offset, - 32 KB + 4*/
        err = create_cond_branch(&instr, iptr, addr - 0x8004, flags);

@@ -576,7 +586,8 @@ static void __init test_branch_bform(void)

        /* Check flags are masked correctly */
        err = create_cond_branch(&instr, iptr, addr, 0xFFFFFFFC);
-       check(instr_is_branch_to_addr(&instr, addr));
+       patch_instruction(iptr, instr);
+       check(instr_is_branch_to_addr(iptr, addr));
        check(ppc_inst_equal(instr, ppc_inst(0x43FF0000)));
 }

--

2.25.0