[U-Boot] [PATCH 5/5] arm: optimize relocate_code routine

Albert ARIBAUD
2013-05-15T07:32:47Z

Hi Beno?t,

On Wed, 15 May 2013 01:54:11 +0200 (CEST), Beno?t Th?baudeau
<benoit.thebaudeau@advansee.com> wrote:

> Hi Albert,
>
> On Tuesday, May 14, 2013 10:03:00 PM, Albert ARIBAUD wrote:
> > Use section symbols directly
> > Drop support for R_ARM_ABS32 record types
> > Eliminate unneeded intermediate registers
> > Optimize relocation table iteration
> >
> > Signed-off-by: Albert ARIBAUD <albert.u.boot@aribaud.net>
> > ---
> > arch/arm/lib/relocate.S | 45 +++++++++++++++------------------------------
> > 1 file changed, 15 insertions(+), 30 deletions(-)
> >
> > diff --git a/arch/arm/lib/relocate.S b/arch/arm/lib/relocate.S
> > index 818735c..75ee3b4 100644
> > --- a/arch/arm/lib/relocate.S
> > +++ b/arch/arm/lib/relocate.S
> > @@ -37,51 +37,36 @@
> > * This function relocates the monitor code.
> > */
> > ENTRY(relocate_code)
> > - mov r6, r0 /* save addr of destination */
> >
> > - ldr r0, =__image_copy_start /* r0 <- source start address */
> > - subs r9, r6, r0 /* r9 <- relocation offset */
> > + ldr r1, =__image_copy_start /* r1 <- source start address */
> > + subs r9, r0, r1 /* r9 <- relocation offset */
> > beq relocate_done /* skip relocation */
> > - mov r1, r6 /* r1 <- scratch for copy loop */
> > ldr r2, =__image_copy_end /* r2 <- source end address */
> >
> > copy_loop:
> > - ldmia r0!, {r10-r11} /* copy from source address [r0] */
> > - stmia r1!, {r10-r11} /* copy to target address [r1] */
> > - cmp r0, r2 /* until source end address [r2] */
> > + ldmia r1!, {r10-r11} /* copy from source address [r1] */
> > + stmia r0!, {r10-r11} /* copy to target address [r0] */
> > + cmp r1, r2 /* until source end address [r2] */
> > blo copy_loop
> >
> > /*
> > * fix .rel.dyn relocations
> > */
> > - ldr r10, =__dynsym_start /* r10 <- sym table ofs */
> > ldr r2, =__rel_dyn_start /* r2 <- rel dyn start ofs */
> > ldr r3, =__rel_dyn_end /* r3 <- rel dyn end ofs */
> > fixloop:
> > - ldr r0, [r2] /* r0 <- SRC location to fix up */
> > - add r0, r0, r9 /* r0 <- DST location to fix up */
> > - ldr r1, [r2, #4]
> > - and r7, r1, #0xff
> > - cmp r7, #23 /* relative fixup? */
> > - beq fixrel
> > - cmp r7, #2 /* absolute fixup? */
> > - beq fixabs
> > - /* ignore unknown type of fixup */
> > - b fixnext
> > -fixabs:
> > - /* absolute fix: set location to (offset) symbol value */
> > - mov r1, r1, LSR #4 /* r1 <- symbol index in .dynsym */
> > - add r1, r10, r1 /* r1 <- address of symbol in table */
> > - ldr r1, [r1, #4] /* r1 <- symbol value */
> > - add r1, r1, r9 /* r1 <- relocated sym addr */
> > - b fixnext
> > -fixrel:
> > + ldmia r2!, {r0-r1} /* (r0,r1) <- (SRC location,fixup) */
> > + and r1, r1, #0xff /* r1 <- fixup type */
> > + cmp r1, #23 /* relative fixup? */
> > + bne fixnext
> > +
> > /* relative fix: increase location by offset */
> > - ldr r1, [r0]
> > - add r1, r1, r9
> > + add r0, r0, r9 /* r0 <- DST location to fix up */
> > + ldr r1, [r0] /* r1 <- content to fix up */
> > + add r1, r1, r9 /* fix up */
> > + str r1, [r0] /* write back fixed-up content */
> > +
> > fixnext:
> > - str r1, [r0]
> > - add r2, r2, #8 /* each rel.dyn entry is 8 bytes */
> > cmp r2, r3
> > blo fixloop
>
> The final state of relocate.S is correct in this series, but it is not correct
> at the end of "[PATCH v2 4/4] arm: factorize relocate_code routine" as I pointed
> out in the part of my review that you cut in your first reply.

Error is relocate patch series to be fixed in V2; I'll rebase V2 of
this series accordingly.

Thanks again.

> Best regards,
> Beno?t

Amicalement,
--
Albert.