Re: [Xen-ia64-devel] [PATCH][GFW] fix unalignment ref with gcc 4.x

[Kouya Shimura <kouya@xxxxxxxxxxxxxx>]

Hi Yamahata-san,

Thanks for informing me.
My gcc might be Redhat patched one. (I'm using RHEL5)
It generates the code I expect. 

So I rewrote the patch more generally.

Tristan, please discard the previous patch and apply
the attached patch. 

Thanks,
Kouya

Signed-off-by: Kouya Shimura <kouya@xxxxxxxxxxxxxx>

Isaku Yamahata writes:
 > Hi.
 > 
 > gcc doesn't support aligned attribute for values on stack.
 > See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16660
 > 
 > To be honest, I'm not sure about latest one.
 > At least my ia64-unknown-linux-gcc 4.1.2 which I compiled from
 > the source code doesn't.
 > 
 > Is your gcc the RedHat patched one?
 > Did you check the resulted assembler code?
 > 
 > On Mon, Oct 15, 2007 at 05:59:59PM +0900, Kouya Shimura wrote:
 > Content-Description: message body text
 > > Hi Tristan,
 > > 
 > > The attached patch fix unalignment reference with gcc 4.x.
 > > I tested the binary built with gcc 4.1.1 works fine.
 > > 
 > > Thanks,
 > > Kouya
 > > 
 > > Signed-off-by: Kouya Shimura <kouya@xxxxxxxxxxxxxx>
 > > 
 > 
 > > diff -r 8ecccd88813c edk2-sparse/EdkXenPkg/Cpu/Itanium/Timer/Dxe/Timer.c
 > > --- a/edk2-sparse/EdkXenPkg/Cpu/Itanium/Timer/Dxe/Timer.c  Thu Oct 11 
 > > 02:09:46 2007 +0200
 > > +++ b/edk2-sparse/EdkXenPkg/Cpu/Itanium/Timer/Dxe/Timer.c  Mon Oct 15 
 > > 15:50:46 2007 +0900
 > > @@ -421,15 +421,15 @@ VOID
 > >  VOID
 > >  check_regs (VOID)
 > >  {
 > > -  long save[SAVESZ / 8];
 > > -  long rand[RANDSZ / 8];
 > > +  long save[SAVESZ / 8] __attribute__ ((aligned (16)));
 > > +  long rand[RANDSZ / 8] __attribute__ ((aligned (16)));
 > >    long *r;
 > >    int     i;
 > >  
 > >    for (i = 0; i < RANDSZ; i++)
 > >      ((unsigned char*)rand)[i] = i ^ 0x59;
 > >  
 > > -  if (r = regcheck(save, rand)) {
 > > +  if ((r = regcheck(save, rand))) {
 > >      int reg = r - rand;
 > >      asm volatile ("rsm psr.ic;; mov r2=%0; break 4" : : "r"(reg));
 > >  #if 0
 > 
 > > _______________________________________________
 > > Xen-ia64-devel mailing list
 > > Xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
 > > http://lists.xensource.com/xen-ia64-devel
 > 
 > -- 
 > yamahata

diff -r 8ecccd88813c edk2-sparse/EdkXenPkg/Cpu/Itanium/Timer/Dxe/Timer.c
--- a/edk2-sparse/EdkXenPkg/Cpu/Itanium/Timer/Dxe/Timer.c       Thu Oct 11 
02:09:46 2007 +0200
+++ b/edk2-sparse/EdkXenPkg/Cpu/Itanium/Timer/Dxe/Timer.c       Mon Oct 15 
18:40:16 2007 +0900
@@ -421,15 +421,23 @@ VOID
 VOID
 check_regs (VOID)
 {
-       long save[SAVESZ / 8];
-       long rand[RANDSZ / 8];
+       long save_stk[SAVESZ / 8 + 1];
+       long rand_stk[RANDSZ / 8 + 1];
+       long *save = save_stk;
+       long *rand = rand_stk;
        long *r;
        int     i;
 
+       /* 16 bytes alignment */
+       if (((long)save & 8) != 0)
+           ++save;
+       if (((long)rand & 8) != 0)
+           ++rand;
+
        for (i = 0; i < RANDSZ; i++)
          ((unsigned char*)rand)[i] = i ^ 0x59;
 
-       if (r = regcheck(save, rand)) {
+       if ((r = regcheck(save, rand))) {
          int reg = r - rand;
          asm volatile ("rsm psr.ic;; mov r2=%0; break 4" : : "r"(reg));
 #if 0

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