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microblaze: At swx, check that the reserved word is unmodified
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This improves the reservation check for system emulation, making
it possible to catch stores that modify reserved word.

Signed-off-by: Edgar E. Iglesias <[email protected]>
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edgarigl committed Oct 24, 2013
1 parent 4a53627 commit 11a7621
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Showing 2 changed files with 17 additions and 0 deletions.
1 change: 1 addition & 0 deletions target-microblaze/cpu.h
Original file line number Diff line number Diff line change
Expand Up @@ -246,6 +246,7 @@ struct CPUMBState {
/* lwx/swx reserved address */
#define RES_ADDR_NONE 0xffffffff /* Use 0xffffffff to indicate no reservation */
uint32_t res_addr;
uint32_t res_val;

/* Internal flags. */
#define IMM_FLAG 4
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16 changes: 16 additions & 0 deletions target-microblaze/translate.c
Original file line number Diff line number Diff line change
Expand Up @@ -50,6 +50,7 @@ static TCGv env_btaken;
static TCGv env_btarget;
static TCGv env_iflags;
static TCGv env_res_addr;
static TCGv env_res_val;

#include "exec/gen-icount.h"

Expand Down Expand Up @@ -879,6 +880,7 @@ static inline void gen_load(DisasContext *dc, TCGv dst, TCGv addr,

if (exclusive) {
tcg_gen_mov_tl(env_res_addr, addr);
tcg_gen_mov_tl(env_res_val, dst);
}
}

Expand Down Expand Up @@ -1128,6 +1130,7 @@ static void dec_store(DisasContext *dc)

swx_addr = tcg_temp_local_new();
if (ex) { /* swx */
TCGv tval;

/* Force addr into the swx_addr. */
tcg_gen_mov_tl(swx_addr, *addr);
Expand All @@ -1138,7 +1141,17 @@ static void dec_store(DisasContext *dc)
write_carryi(dc, 1);
swx_skip = gen_new_label();
tcg_gen_brcond_tl(TCG_COND_NE, env_res_addr, swx_addr, swx_skip);

/* Compare the value loaded at lwx with current contents of
the reserved location.
FIXME: This only works for system emulation where we can expect
this compare and the following write to be atomic. For user
emulation we need to add atomicity between threads. */
tval = tcg_temp_new();
gen_load(dc, tval, swx_addr, 4, false);
tcg_gen_brcond_tl(TCG_COND_NE, env_res_val, tval, swx_skip);
write_carryi(dc, 0);
tcg_temp_free(tval);
}

if (rev && size != 4) {
Expand Down Expand Up @@ -2009,6 +2022,9 @@ void mb_tcg_init(void)
env_res_addr = tcg_global_mem_new(TCG_AREG0,
offsetof(CPUMBState, res_addr),
"res_addr");
env_res_val = tcg_global_mem_new(TCG_AREG0,
offsetof(CPUMBState, res_val),
"res_val");
for (i = 0; i < ARRAY_SIZE(cpu_R); i++) {
cpu_R[i] = tcg_global_mem_new(TCG_AREG0,
offsetof(CPUMBState, regs[i]),
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