m, mw, md, mp, mpw, and mpd subcommands

Edit online

The m (modify bytes), mw (modify words) and md (modify double words) subcommands modify memory starting at a specified effective address. The mp (modify bytes), mpw (modify words) and mpd (modify double words) subcommands modify memory starting at a specified real address.

These subcommands are only available within the KDB kernel debugger. They are not included in the kdb command.

Format

m effectiveaddress

mw effectiveaddress

md effectiveaddress

mp physicaladdress

mpw physicaladdress

mpd physicaladdress

Parameters

Item	Description
effectiveaddress	Specifies the effective or virtual address of the starting memory area to modify. Symbols, hexadecimal values, or hexadecimal expressions can be used to specify the address.
physicaladdress	Specifies the physical or real address of the starting memory area to modify. Symbols, hexadecimal values, or hexadecimal expressions can be used to specify the address.

Read or write access can be in virtual or real mode.

These subcommands are interactive. Each modification is entered one-by-one. The first unexpected input stops modification. For example, a period (.) can be used to indicate the end of the data. If a break point is set at the same address, use the mw subcommand to maintain break point coherency.

Note: Symbolic expressions are not allowed as input.

Other

No aliases.

Examples

The following is an example of how to use the mw and m subcommands to do a patch:

KDB(0)> dc @iar //print current instruction
   .open+000000    mflr    r0
   KDB(0)> mw @iar //nop current instruction
   .open+000000:  7C0802A6  = 60000000
   .open+000004:  93E1FFFC  = . //end of input
   KDB(0)> dc @iar //print current instruction
   .open+000000     ori    r0,r0,0
   KDB(0)> m @iar //restore current instruction byte per byte
   .open+000000:  60  = 7C
   .open+000001:  00  = 08
   .open+000002:  00  = 02
   .open+000003:  00  = A6
   .open+000004:  93  = . //end of input
   KDB(0)> dc @iar //print current instruction
   .open+000000    mflr    r0
   KDB(0)> tr @iar //physical address of current instruction
   Physical Address = 001C5BA0
   KDB(0)> mwp 001C5BA0 //modify with physical address
   001C5BA0:  7C0802A6  = <CR/LF>
   001C5BA4:  93E1FFFC  = <CR/LF>
   001C5BA8:  90010008  = <CR/LF>
   001C5BAC:  9421FF40  = 60000000
   001C5BB0:  83E211C4  = . //end of input
   KDB(0)> dc @iar 5 //print instructions
   .open+000000    mflr    r0
   .open+000004     stw    r31,FFFFFFFC(stkp)
   .open+000008     stw    r0,8(stkp)
   .open+00000C     ori    r0,r0,0
   .open+000010     lwz    r31,11C4(toc)       11C4(toc)=_open$$
   KDB(0)> mw open+c //restore instruction
   .open+00000C:  60000000  = 9421FF40
   .open+000010:  83E211C4  = . //end of input
   KDB(0)> dc open+c //print instruction
   .open+00000C    stwu    stkp,FFFFFF40(stkp)
   KDB(0)>