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    Subject[ 22/42] kgdb,debug_core: pass the breakpoint struct instead of address and memory
    3.0-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Jason Wessel <jason.wessel@windriver.com>

    commit 98b54aa1a2241b59372468bd1e9c2d207bdba54b upstream.

    There is extra state information that needs to be exposed in the
    kgdb_bpt structure for tracking how a breakpoint was installed. The
    debug_core only uses the the probe_kernel_write() to install
    breakpoints, but this is not enough for all the archs. Some arch such
    as x86 need to use text_poke() in order to install a breakpoint into a
    read only page.

    Passing the kgdb_bpt structure to kgdb_arch_set_breakpoint() and
    kgdb_arch_remove_breakpoint() allows other archs to set the type
    variable which indicates how the breakpoint was installed.

    Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    include/linux/kgdb.h | 4 +--
    kernel/debug/debug_core.c | 53 ++++++++++++++++++++--------------------------
    2 files changed, 26 insertions(+), 31 deletions(-)

    --- a/include/linux/kgdb.h
    +++ b/include/linux/kgdb.h
    @@ -207,8 +207,8 @@ extern void kgdb_arch_set_pc(struct pt_r

    /* Optional functions. */
    extern int kgdb_validate_break_address(unsigned long addr);
    -extern int kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr);
    -extern int kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle);
    +extern int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt);
    +extern int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt);

    /**
    * kgdb_arch_late - Perform any architecture specific initalization.
    --- a/kernel/debug/debug_core.c
    +++ b/kernel/debug/debug_core.c
    @@ -157,37 +157,39 @@ early_param("nokgdbroundup", opt_nokgdbr
    * Weak aliases for breakpoint management,
    * can be overriden by architectures when needed:
    */
    -int __weak kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr)
    +int __weak kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
    {
    int err;

    - err = probe_kernel_read(saved_instr, (char *)addr, BREAK_INSTR_SIZE);
    + err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr,
    + BREAK_INSTR_SIZE);
    if (err)
    return err;
    -
    - return probe_kernel_write((char *)addr, arch_kgdb_ops.gdb_bpt_instr,
    - BREAK_INSTR_SIZE);
    + err = probe_kernel_write((char *)bpt->bpt_addr,
    + arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE);
    + return err;
    }

    -int __weak kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle)
    +int __weak kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
    {
    - return probe_kernel_write((char *)addr,
    - (char *)bundle, BREAK_INSTR_SIZE);
    + return probe_kernel_write((char *)bpt->bpt_addr,
    + (char *)bpt->saved_instr, BREAK_INSTR_SIZE);
    }

    int __weak kgdb_validate_break_address(unsigned long addr)
    {
    - char tmp_variable[BREAK_INSTR_SIZE];
    + struct kgdb_bkpt tmp;
    int err;
    - /* Validate setting the breakpoint and then removing it. In the
    + /* Validate setting the breakpoint and then removing it. If the
    * remove fails, the kernel needs to emit a bad message because we
    * are deep trouble not being able to put things back the way we
    * found them.
    */
    - err = kgdb_arch_set_breakpoint(addr, tmp_variable);
    + tmp.bpt_addr = addr;
    + err = kgdb_arch_set_breakpoint(&tmp);
    if (err)
    return err;
    - err = kgdb_arch_remove_breakpoint(addr, tmp_variable);
    + err = kgdb_arch_remove_breakpoint(&tmp);
    if (err)
    printk(KERN_ERR "KGDB: Critical breakpoint error, kernel "
    "memory destroyed at: %lx", addr);
    @@ -231,7 +233,6 @@ static void kgdb_flush_swbreak_addr(unsi
    */
    int dbg_activate_sw_breakpoints(void)
    {
    - unsigned long addr;
    int error;
    int ret = 0;
    int i;
    @@ -240,16 +241,15 @@ int dbg_activate_sw_breakpoints(void)
    if (kgdb_break[i].state != BP_SET)
    continue;

    - addr = kgdb_break[i].bpt_addr;
    - error = kgdb_arch_set_breakpoint(addr,
    - kgdb_break[i].saved_instr);
    + error = kgdb_arch_set_breakpoint(&kgdb_break[i]);
    if (error) {
    ret = error;
    - printk(KERN_INFO "KGDB: BP install failed: %lx", addr);
    + printk(KERN_INFO "KGDB: BP install failed: %lx",
    + kgdb_break[i].bpt_addr);
    continue;
    }

    - kgdb_flush_swbreak_addr(addr);
    + kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr);
    kgdb_break[i].state = BP_ACTIVE;
    }
    return ret;
    @@ -298,7 +298,6 @@ int dbg_set_sw_break(unsigned long addr)

    int dbg_deactivate_sw_breakpoints(void)
    {
    - unsigned long addr;
    int error;
    int ret = 0;
    int i;
    @@ -306,15 +305,14 @@ int dbg_deactivate_sw_breakpoints(void)
    for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
    if (kgdb_break[i].state != BP_ACTIVE)
    continue;
    - addr = kgdb_break[i].bpt_addr;
    - error = kgdb_arch_remove_breakpoint(addr,
    - kgdb_break[i].saved_instr);
    + error = kgdb_arch_remove_breakpoint(&kgdb_break[i]);
    if (error) {
    - printk(KERN_INFO "KGDB: BP remove failed: %lx\n", addr);
    + printk(KERN_INFO "KGDB: BP remove failed: %lx\n",
    + kgdb_break[i].bpt_addr);
    ret = error;
    }

    - kgdb_flush_swbreak_addr(addr);
    + kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr);
    kgdb_break[i].state = BP_SET;
    }
    return ret;
    @@ -348,7 +346,6 @@ int kgdb_isremovedbreak(unsigned long ad

    int dbg_remove_all_break(void)
    {
    - unsigned long addr;
    int error;
    int i;

    @@ -356,12 +353,10 @@ int dbg_remove_all_break(void)
    for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
    if (kgdb_break[i].state != BP_ACTIVE)
    goto setundefined;
    - addr = kgdb_break[i].bpt_addr;
    - error = kgdb_arch_remove_breakpoint(addr,
    - kgdb_break[i].saved_instr);
    + error = kgdb_arch_remove_breakpoint(&kgdb_break[i]);
    if (error)
    printk(KERN_ERR "KGDB: breakpoint remove failed: %lx\n",
    - addr);
    + kgdb_break[i].bpt_addr);
    setundefined:
    kgdb_break[i].state = BP_UNDEFINED;
    }



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