Commit 1938ca88 authored by Michael Holzheu's avatar Michael Holzheu Committed by Kamal Mostafa

s390/dis: Fix handling of format specifiers

commit 272fa59c upstream.

The print_insn() function returns strings like "lghi %r1,0". To escape the
'%' character in sprintf() a second '%' is used. For example "lghi %%r1,0"
is converted into "lghi %r1,0".

After print_insn() the output string is passed to printk(). Because format
specifiers like "%r" or "%f" are ignored by printk() this works by chance
most of the time. But for instructions with control registers like
"lctl %c6,%c6,780" this fails because printk() interprets "%c" as
character format specifier.

Fix this problem and escape the '%' characters twice.

For example "lctl %%%%c6,%%%%c6,780" is then converted by sprintf()
into "lctl %%c6,%%c6,780" and by printk() into "lctl %c6,%c6,780".
Signed-off-by: default avatarMichael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
[ luis: backported to 3.16:
  - drop condition with OPERAND_VR introduced only with commit
    3585cb02 ("s390/disassembler: add vector instructions") ]
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
parent b7827ba5
...@@ -1726,14 +1726,21 @@ static int print_insn(char *buffer, unsigned char *code, unsigned long addr) ...@@ -1726,14 +1726,21 @@ static int print_insn(char *buffer, unsigned char *code, unsigned long addr)
} }
if (separator) if (separator)
ptr += sprintf(ptr, "%c", separator); ptr += sprintf(ptr, "%c", separator);
/*
* Use four '%' characters below because of the
* following two conversions:
*
* 1) sprintf: %%%%r -> %%r
* 2) printk : %%r -> %r
*/
if (operand->flags & OPERAND_GPR) if (operand->flags & OPERAND_GPR)
ptr += sprintf(ptr, "%%r%i", value); ptr += sprintf(ptr, "%%%%r%i", value);
else if (operand->flags & OPERAND_FPR) else if (operand->flags & OPERAND_FPR)
ptr += sprintf(ptr, "%%f%i", value); ptr += sprintf(ptr, "%%%%f%i", value);
else if (operand->flags & OPERAND_AR) else if (operand->flags & OPERAND_AR)
ptr += sprintf(ptr, "%%a%i", value); ptr += sprintf(ptr, "%%%%a%i", value);
else if (operand->flags & OPERAND_CR) else if (operand->flags & OPERAND_CR)
ptr += sprintf(ptr, "%%c%i", value); ptr += sprintf(ptr, "%%%%c%i", value);
else if (operand->flags & OPERAND_PCREL) else if (operand->flags & OPERAND_PCREL)
ptr += sprintf(ptr, "%lx", (signed int) value ptr += sprintf(ptr, "%lx", (signed int) value
+ addr); + addr);
......
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