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Commit 23637568 authored by Jonathan Nieder's avatar Jonathan Nieder Committed by Ingo Molnar
Browse files

x86: Fix kprobes build with non-gawk awk 



The instruction attribute table generator fails when run by mawk
or original-awk:

 $ mawk -f arch/x86/tools/gen-insn-attr-x86.awk \
	arch/x86/lib/x86-opcode-map.txt > /dev/null
 Semantic error at 240: Second IMM error
 $ echo $?
 1

Line 240 contains "c8: ENTER Iw,Ib", which indicates that this
instruction has two immediate operands, the second of which is
one byte.  The script loops through the immediate operands using
a for loop.

Unfortunately, there is no guarantee in awk that a for (variable
in array) loop will return the indices in increasing order.
Internally, both original-awk and mawk iterate over a hash table
for this purpose, and both implementations happen to produce the
index 2 before 1.  The supposed second immediate operand is more
than one byte wide, producing the error.

So loop over the indices in increasing order instead.  As a
side-effect, with mawk this means the silly two-entry hash table
never has to be built.

Signed-off-by: default avatarJonathan Nieder <jrnieder@gmail.com>
Acked-by Masami Hiramatsu <mhiramat@redhat.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20091213220437.GA27718@progeny.tock>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent bf08b3b1

arch/x86/tools/gen-insn-attr-x86.awk

+5 −5
Original line number Diff line number Diff line
@@ -226,12 +226,12 @@ function add_flags(old,new) { 
}



# convert operands to flags.

function convert_operands(opnd,       i,imm,mod)

function convert_operands(count,opnd,       i,j,imm,mod)

{

	imm = null

	mod = null

	for (i in opnd) {

		i  = opnd[i]

	for (j = 1; j <= count; j++) {

		i = opnd[j]

		if (match(i, imm_expr) == 1) {

			if (!imm_flag[i])

				semantic_error("Unknown imm opnd: " i)
@@ -282,8 +282,8 @@ function convert_operands(opnd, i,imm,mod) 
		# parse one opcode

		if (match($i, opnd_expr)) {

			opnd = $i

			split($(i++), opnds, ",")

			flags = convert_operands(opnds)

			count = split($(i++), opnds, ",")

			flags = convert_operands(count, opnds)

		}

		if (match($i, ext_expr))

			ext = $(i++)