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target-i386: Fix lcall/ljmp to call gate in IA-32e mode

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Currently call gates are always treated as 32-bit gates.  In IA-32e mode
(either compatibility or 64-bit submode), system segment descriptors are
always 64-bit.  Treating them as 32-bit has the expected unfortunate
effect: only the lower 32 bits of the offset are loaded, the stack
pointer is truncated, a bad new stack pointer is loaded from the TSS (if
switching privilege levels), etc.

This change adds support for 64-bit call gate to the lcall and ljmp
instructions.  Additionally, there should be a check for non-canonical
stack pointers, but I've omitted that since there doesn't seem to be
checks for non-canonical addresses in this code elsewhere.

I've left the raise_exception_err_ra lines unwapped at 80 columns to
match the style in the rest of the file.

Signed-off-by: Andrew Oates <aoates@google.com>
Message-Id: <20180819181725.34098-1-andrew@andrewoates.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Andrew Oates 2018-08-19 14:17:25 -04:00 committed by Paolo Bonzini
parent 692fbdf9f4
commit 0aca060526
1 changed files with 152 additions and 40 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

192
target/i386/seg_helper.c
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@ -518,6 +518,11 @@ static void switch_tss(CPUX86State *env, int tss_selector,
static inline unsigned int get_sp_mask(unsigned int e2)
{
#ifdef TARGET_X86_64
if (e2 & DESC_L_MASK) {
return 0;
} else
#endif
if (e2 & DESC_B_MASK) {
return 0xffffffff;
} else {
@ -1640,6 +1645,14 @@ void helper_ljmp_protected(CPUX86State *env, int new_cs, target_ulong new_eip,
rpl = new_cs & 3;
cpl = env->hflags & HF_CPL_MASK;
type = (e2 >> DESC_TYPE_SHIFT) & 0xf;
#ifdef TARGET_X86_64
if (env->efer & MSR_EFER_LMA) {
if (type != 12) {
raise_exception_err_ra(env, EXCP0D_GPF, new_cs & 0xfffc, GETPC());
}
}
#endif
switch (type) {
case 1: /* 286 TSS */
case 9: /* 386 TSS */
@ -1662,6 +1675,23 @@ void helper_ljmp_protected(CPUX86State *env, int new_cs, target_ulong new_eip,
if (type == 12) {
new_eip |= (e2 & 0xffff0000);
}
#ifdef TARGET_X86_64
if (env->efer & MSR_EFER_LMA) {
/* load the upper 8 bytes of the 64-bit call gate */
if (load_segment_ra(env, &e1, &e2, new_cs + 8, GETPC())) {
raise_exception_err_ra(env, EXCP0D_GPF, new_cs & 0xfffc,
GETPC());
}
type = (e2 >> DESC_TYPE_SHIFT) & 0x1f;
if (type != 0) {
raise_exception_err_ra(env, EXCP0D_GPF, new_cs & 0xfffc,
GETPC());
}
new_eip |= ((target_ulong)e1) << 32;
}
#endif
if (load_segment_ra(env, &e1, &e2, gate_cs, GETPC()) != 0) {
raise_exception_err_ra(env, EXCP0D_GPF, gate_cs & 0xfffc, GETPC());
}
@ -1675,11 +1705,22 @@ void helper_ljmp_protected(CPUX86State *env, int new_cs, target_ulong new_eip,
(!(e2 & DESC_C_MASK) && (dpl != cpl))) {
raise_exception_err_ra(env, EXCP0D_GPF, gate_cs & 0xfffc, GETPC());
}
#ifdef TARGET_X86_64
if (env->efer & MSR_EFER_LMA) {
if (!(e2 & DESC_L_MASK)) {
raise_exception_err_ra(env, EXCP0D_GPF, gate_cs & 0xfffc, GETPC());
}
if (e2 & DESC_B_MASK) {
raise_exception_err_ra(env, EXCP0D_GPF, gate_cs & 0xfffc, GETPC());
}
}
#endif
if (!(e2 & DESC_P_MASK)) {
raise_exception_err_ra(env, EXCP0D_GPF, gate_cs & 0xfffc, GETPC());
}
limit = get_seg_limit(e1, e2);
if (new_eip > limit) {
if (new_eip > limit &&
(!(env->hflags & HF_LMA_MASK) || !(e2 & DESC_L_MASK))) {
raise_exception_err_ra(env, EXCP0D_GPF, 0, GETPC());
}
cpu_x86_load_seg_cache(env, R_CS, (gate_cs & 0xfffc) | cpl,
@ -1724,12 +1765,12 @@ void helper_lcall_protected(CPUX86State *env, int new_cs, target_ulong new_eip,
int shift, target_ulong next_eip)
{
int new_stack, i;
uint32_t e1, e2, cpl, dpl, rpl, selector, offset, param_count;
uint32_t ss = 0, ss_e1 = 0, ss_e2 = 0, sp, type, ss_dpl, sp_mask;
uint32_t e1, e2, cpl, dpl, rpl, selector, param_count;
uint32_t ss = 0, ss_e1 = 0, ss_e2 = 0, type, ss_dpl, sp_mask;
uint32_t val, limit, old_sp_mask;
target_ulong ssp, old_ssp;
target_ulong ssp, old_ssp, offset, sp;
LOG_PCALL("lcall %04x:%08x s=%d\n", new_cs, (uint32_t)new_eip, shift);
LOG_PCALL("lcall %04x:" TARGET_FMT_lx " s=%d\n", new_cs, new_eip, shift);
LOG_PCALL_STATE(CPU(x86_env_get_cpu(env)));
if ((new_cs & 0xfffc) == 0) {
raise_exception_err_ra(env, EXCP0D_GPF, 0, GETPC());
@ -1807,6 +1848,15 @@ void helper_lcall_protected(CPUX86State *env, int new_cs, target_ulong new_eip,
type = (e2 >> DESC_TYPE_SHIFT) & 0x1f;
dpl = (e2 >> DESC_DPL_SHIFT) & 3;
rpl = new_cs & 3;
#ifdef TARGET_X86_64
if (env->efer & MSR_EFER_LMA) {
if (type != 12) {
raise_exception_err_ra(env, EXCP0D_GPF, new_cs & 0xfffc, GETPC());
}
}
#endif
switch (type) {
case 1: /* available 286 TSS */
case 9: /* available 386 TSS */
@ -1833,8 +1883,23 @@ void helper_lcall_protected(CPUX86State *env, int new_cs, target_ulong new_eip,
raise_exception_err_ra(env, EXCP0B_NOSEG, new_cs & 0xfffc, GETPC());
}
selector = e1 >> 16;
offset = (e2 & 0xffff0000) | (e1 & 0x0000ffff);
param_count = e2 & 0x1f;
offset = (e2 & 0xffff0000) | (e1 & 0x0000ffff);
#ifdef TARGET_X86_64
if (env->efer & MSR_EFER_LMA) {
/* load the upper 8 bytes of the 64-bit call gate */
if (load_segment_ra(env, &e1, &e2, new_cs + 8, GETPC())) {
raise_exception_err_ra(env, EXCP0D_GPF, new_cs & 0xfffc,
GETPC());
}
type = (e2 >> DESC_TYPE_SHIFT) & 0x1f;
if (type != 0) {
raise_exception_err_ra(env, EXCP0D_GPF, new_cs & 0xfffc,
GETPC());
}
offset |= ((target_ulong)e1) << 32;
}
#endif
if ((selector & 0xfffc) == 0) {
raise_exception_err_ra(env, EXCP0D_GPF, 0, GETPC());
}
@ -1849,46 +1914,80 @@ void helper_lcall_protected(CPUX86State *env, int new_cs, target_ulong new_eip,
if (dpl > cpl) {
raise_exception_err_ra(env, EXCP0D_GPF, selector & 0xfffc, GETPC());
}
#ifdef TARGET_X86_64
if (env->efer & MSR_EFER_LMA) {
if (!(e2 & DESC_L_MASK)) {
raise_exception_err_ra(env, EXCP0D_GPF, selector & 0xfffc, GETPC());
}
if (e2 & DESC_B_MASK) {
raise_exception_err_ra(env, EXCP0D_GPF, selector & 0xfffc, GETPC());
}
shift++;
}
#endif
if (!(e2 & DESC_P_MASK)) {
raise_exception_err_ra(env, EXCP0B_NOSEG, selector & 0xfffc, GETPC());
}
if (!(e2 & DESC_C_MASK) && dpl < cpl) {
/* to inner privilege */
get_ss_esp_from_tss(env, &ss, &sp, dpl, GETPC());
LOG_PCALL("new ss:esp=%04x:%08x param_count=%d env->regs[R_ESP]="
TARGET_FMT_lx "\n", ss, sp, param_count,
env->regs[R_ESP]);
if ((ss & 0xfffc) == 0) {
raise_exception_err_ra(env, EXCP0A_TSS, ss & 0xfffc, GETPC());
}
if ((ss & 3) != dpl) {
raise_exception_err_ra(env, EXCP0A_TSS, ss & 0xfffc, GETPC());
}
if (load_segment_ra(env, &ss_e1, &ss_e2, ss, GETPC()) != 0) {
raise_exception_err_ra(env, EXCP0A_TSS, ss & 0xfffc, GETPC());
}
ss_dpl = (ss_e2 >> DESC_DPL_SHIFT) & 3;
if (ss_dpl != dpl) {
raise_exception_err_ra(env, EXCP0A_TSS, ss & 0xfffc, GETPC());
}
if (!(ss_e2 & DESC_S_MASK) ||
(ss_e2 & DESC_CS_MASK) ||
!(ss_e2 & DESC_W_MASK)) {
raise_exception_err_ra(env, EXCP0A_TSS, ss & 0xfffc, GETPC());
}
if (!(ss_e2 & DESC_P_MASK)) {
raise_exception_err_ra(env, EXCP0A_TSS, ss & 0xfffc, GETPC());
#ifdef TARGET_X86_64
if (shift == 2) {
sp = get_rsp_from_tss(env, dpl);
ss = dpl; /* SS = NULL selector with RPL = new CPL */
new_stack = 1;
sp_mask = 0;
ssp = 0; /* SS base is always zero in IA-32e mode */
LOG_PCALL("new ss:rsp=%04x:%016llx env->regs[R_ESP]="
TARGET_FMT_lx "\n", ss, sp, env->regs[R_ESP]);
} else
#endif
{
uint32_t sp32;
get_ss_esp_from_tss(env, &ss, &sp32, dpl, GETPC());
LOG_PCALL("new ss:esp=%04x:%08x param_count=%d env->regs[R_ESP]="
TARGET_FMT_lx "\n", ss, sp32, param_count,
env->regs[R_ESP]);
sp = sp32;
if ((ss & 0xfffc) == 0) {
raise_exception_err_ra(env, EXCP0A_TSS, ss & 0xfffc, GETPC());
}
if ((ss & 3) != dpl) {
raise_exception_err_ra(env, EXCP0A_TSS, ss & 0xfffc, GETPC());
}
if (load_segment_ra(env, &ss_e1, &ss_e2, ss, GETPC()) != 0) {
raise_exception_err_ra(env, EXCP0A_TSS, ss & 0xfffc, GETPC());
}
ss_dpl = (ss_e2 >> DESC_DPL_SHIFT) & 3;
if (ss_dpl != dpl) {
raise_exception_err_ra(env, EXCP0A_TSS, ss & 0xfffc, GETPC());
}
if (!(ss_e2 & DESC_S_MASK) ||
(ss_e2 & DESC_CS_MASK) ||
!(ss_e2 & DESC_W_MASK)) {
raise_exception_err_ra(env, EXCP0A_TSS, ss & 0xfffc, GETPC());
}
if (!(ss_e2 & DESC_P_MASK)) {
raise_exception_err_ra(env, EXCP0A_TSS, ss & 0xfffc, GETPC());
}
sp_mask = get_sp_mask(ss_e2);
ssp = get_seg_base(ss_e1, ss_e2);
}
/* push_size = ((param_count * 2) + 8) << shift; */
old_sp_mask = get_sp_mask(env->segs[R_SS].flags);
old_ssp = env->segs[R_SS].base;
sp_mask = get_sp_mask(ss_e2);
ssp = get_seg_base(ss_e1, ss_e2);
if (shift) {
#ifdef TARGET_X86_64
if (shift == 2) {
/* XXX: verify if new stack address is canonical */
PUSHQ_RA(sp, env->segs[R_SS].selector, GETPC());
PUSHQ_RA(sp, env->regs[R_ESP], GETPC());
/* parameters aren't supported for 64-bit call gates */
} else
#endif
if (shift == 1) {
PUSHL_RA(ssp, sp, sp_mask, env->segs[R_SS].selector, GETPC());
PUSHL_RA(ssp, sp, sp_mask, env->regs[R_ESP], GETPC());
for (i = param_count - 1; i >= 0; i--) {
@ -1917,7 +2016,13 @@ void helper_lcall_protected(CPUX86State *env, int new_cs, target_ulong new_eip,
new_stack = 0;
}
if (shift) {
#ifdef TARGET_X86_64
if (shift == 2) {
PUSHQ_RA(sp, env->segs[R_CS].selector, GETPC());
PUSHQ_RA(sp, next_eip, GETPC());
} else
#endif
if (shift == 1) {
PUSHL_RA(ssp, sp, sp_mask, env->segs[R_CS].selector, GETPC());
PUSHL_RA(ssp, sp, sp_mask, next_eip, GETPC());
} else {
@ -1928,11 +2033,18 @@ void helper_lcall_protected(CPUX86State *env, int new_cs, target_ulong new_eip,
/* from this point, not restartable */
if (new_stack) {
ss = (ss & ~3) | dpl;
cpu_x86_load_seg_cache(env, R_SS, ss,
ssp,
get_seg_limit(ss_e1, ss_e2),
ss_e2);
#ifdef TARGET_X86_64
if (shift == 2) {
cpu_x86_load_seg_cache(env, R_SS, ss, 0, 0, 0);
} else
#endif
{
ss = (ss & ~3) | dpl;
cpu_x86_load_seg_cache(env, R_SS, ss,
ssp,
get_seg_limit(ss_e1, ss_e2),
ss_e2);
}
}
selector = (selector & ~3) | dpl;