From dbdf20db537a5369c65330f878ad4905020a8bfa Mon Sep 17 00:00:00 2001 From: Bernd Schmidt Date: Wed, 7 Jan 2009 23:14:38 +0800 Subject: Blackfin arch: Faster C implementation of no-MPU CPLB handler This is a mixture ofcMichael McTernan's patch and the existing cplb-mpu code. We ditch the old cplb-nompu implementation, which is a good example of why a good algorithm in a HLL is preferrable to a bad algorithm written in assembly. Rather than try to construct a table of all posible CPLBs and search it, we just create a (smaller) table of memory regions and their attributes. Some of the data structures are now unified for both the mpu and nompu cases. A lot of needless complexity in cplbinit.c is removed. Further optimizations: * compile cplbmgr.c with a lot of -ffixed-reg options, and omit saving these registers on the stack when entering a CPLB exception. * lose cli/nop/nop/sti sequences for some workarounds - these don't * make sense in an exception context Additional code unification should be possible after this. [Mike Frysinger : - convert CPP if statements to C if statements - remove redundant statements - use a do...while loop rather than a for loop to get slightly better optimization and to avoid gcc "may be used uninitialized" warnings ... we know that the [id]cplb_nr_bounds variables will never be 0, so this is OK - the no-mpu code was the last user of MAX_MEM_SIZE and with that rewritten, we can punt it - add some BUG_ON() checks to make sure we dont overflow the small cplb_bounds array - add i/d cplb entries for the bootrom because there is functions/data in there we want to access - we do not need a NULL trailing entry as any time we access the bounds arrays, we use the nr_bounds variable ] Signed-off-by: Michael McTernan Signed-off-by: Mike Frysinger Signed-off-by: Bernd Schmidt Signed-off-by: Bryan Wu --- arch/blackfin/mach-common/entry.S | 21 +++++++++------------ 1 file changed, 9 insertions(+), 12 deletions(-) (limited to 'arch/blackfin/mach-common') diff --git a/arch/blackfin/mach-common/entry.S b/arch/blackfin/mach-common/entry.S index 0efd5f5b7ba..fae77465137 100644 --- a/arch/blackfin/mach-common/entry.S +++ b/arch/blackfin/mach-common/entry.S @@ -112,24 +112,21 @@ ENTRY(_ex_dcplb_viol) ENTRY(_ex_dcplb_miss) ENTRY(_ex_icplb_miss) (R7:6,P5:4) = [sp++]; - ASTAT = [sp++]; - SAVE_ALL_SYS -#ifdef CONFIG_MPU + /* We leave the previously pushed ASTAT on the stack. */ + SAVE_CONTEXT_CPLB + /* We must load R1 here, _before_ DEBUG_HWTRACE_SAVE, since that * will change the stack pointer. */ R0 = SEQSTAT; R1 = SP; -#endif + DEBUG_HWTRACE_SAVE(p5, r7) -#ifdef CONFIG_MPU + sp += -12; call _cplb_hdr; sp += 12; CC = R0 == 0; IF !CC JUMP _handle_bad_cplb; -#else - call __cplb_hdr; -#endif #ifdef CONFIG_DEBUG_DOUBLEFAULT /* While we were processing this, did we double fault? */ @@ -143,7 +140,8 @@ ENTRY(_ex_icplb_miss) #endif DEBUG_HWTRACE_RESTORE(p5, r7) - RESTORE_ALL_SYS + RESTORE_CONTEXT_CPLB + ASTAT = [SP++]; SP = EX_SCRATCH_REG; rtx; ENDPROC(_ex_icplb_miss) @@ -298,9 +296,8 @@ ENTRY(_handle_bad_cplb) * the stack to get ready so, we can fall through - we * need to make a CPLB exception look like a normal exception */ - - RESTORE_ALL_SYS - [--sp] = ASTAT; + RESTORE_CONTEXT_CPLB + /* ASTAT is still on the stack, where it is needed. */ [--sp] = (R7:6,P5:4); ENTRY(_ex_replaceable) -- cgit v1.2.3