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powerpc: Use a function for reading instructions

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Prefixed instructions will mean there are instructions of different
length. As a result dereferencing a pointer to an instruction will not
necessarily give the desired result. Introduce a function for reading
instructions from memory into the instruction data type.

Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Alistair Popple <alistair@popple.id.au>
Link: https://lore.kernel.org/r/20200506034050.24806-13-jniethe5@gmail.com
This commit is contained in:
Jordan Niethe
2020-05-06 13:40:32 +10:00
committed by Michael Ellerman
parent 94afd069d9
commit f8faaffaa7
9 changed files with 33 additions and 26 deletions
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26
arch/powerpc/lib/code-patching.c
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@@ -348,9 +348,9 @@ static unsigned long branch_bform_target(const struct ppc_inst *instr)
unsigned long branch_target(const struct ppc_inst *instr)
{
if (instr_is_branch_iform(*instr))
if (instr_is_branch_iform(ppc_inst_read(instr)))
return branch_iform_target(instr);
else if (instr_is_branch_bform(*instr))
else if (instr_is_branch_bform(ppc_inst_read(instr)))
return branch_bform_target(instr);
return 0;
@@ -358,7 +358,8 @@ unsigned long branch_target(const struct ppc_inst *instr)
int instr_is_branch_to_addr(const struct ppc_inst *instr, unsigned long addr)
{
if (instr_is_branch_iform(*instr) || instr_is_branch_bform(*instr))
if (instr_is_branch_iform(ppc_inst_read(instr)) ||
instr_is_branch_bform(ppc_inst_read(instr)))
return branch_target(instr) == addr;
return 0;
@@ -368,13 +369,14 @@ int translate_branch(struct ppc_inst *instr, const struct ppc_inst *dest,
const struct ppc_inst *src)
{
unsigned long target;
target = branch_target(src);
if (instr_is_branch_iform(*src))
return create_branch(instr, dest, target, ppc_inst_val(*src));
else if (instr_is_branch_bform(*src))
return create_cond_branch(instr, dest, target, ppc_inst_val(*src));
if (instr_is_branch_iform(ppc_inst_read(src)))
return create_branch(instr, dest, target,
ppc_inst_val(ppc_inst_read(src)));
else if (instr_is_branch_bform(ppc_inst_read(src)))
return create_cond_branch(instr, dest, target,
ppc_inst_val(ppc_inst_read(src)));
return 1;
}
@@ -598,7 +600,7 @@ static void __init test_translate_branch(void)
patch_instruction(q, instr);
check(instr_is_branch_to_addr(p, addr));
check(instr_is_branch_to_addr(q, addr));
check(ppc_inst_equal(*q, ppc_inst(0x4a000000)));
check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x4a000000)));
/* Maximum positive case, move x to x - 32 MB + 4 */
p = buf + 0x2000000;
@@ -609,7 +611,7 @@ static void __init test_translate_branch(void)
patch_instruction(q, instr);
check(instr_is_branch_to_addr(p, addr));
check(instr_is_branch_to_addr(q, addr));
check(ppc_inst_equal(*q, ppc_inst(0x49fffffc)));
check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x49fffffc)));
/* Jump to x + 16 MB moved to x + 20 MB */
p = buf;
@@ -655,7 +657,7 @@ static void __init test_translate_branch(void)
patch_instruction(q, instr);
check(instr_is_branch_to_addr(p, addr));
check(instr_is_branch_to_addr(q, addr));
check(ppc_inst_equal(*q, ppc_inst(0x43ff8000)));
check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x43ff8000)));
/* Maximum positive case, move x to x - 32 KB + 4 */
p = buf + 0x8000;
@@ -667,7 +669,7 @@ static void __init test_translate_branch(void)
patch_instruction(q, instr);
check(instr_is_branch_to_addr(p, addr));
check(instr_is_branch_to_addr(q, addr));
check(ppc_inst_equal(*q, ppc_inst(0x43ff7ffc)));
check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x43ff7ffc)));
/* Jump to x + 12 KB moved to x + 20 KB */
p = buf;