motorhead/qemu
1
0
Fork 0
mirror of https://github.com/Motorhead1991/qemu.git synced 2025-08-04 08:13:54 -06:00
Code Issues Projects Releases Packages Wiki Activity Actions

target/arm: Hyp mode R14 is shared with User and System

Browse source 
Hyp mode is an exception to the general rule that each AArch32
mode has its own r13, r14 and SPSR -- it has a banked r13 and
SPSR but shares its r14 with User and System mode. We were
incorrectly implementing it as banked, which meant that on
entry to Hyp mode r14 was 0 rather than the USR/SYS r14.

We provide a new function r14_bank_number() which is like
the existing bank_number() but provides the index into
env->banked_r14[]; bank_number() provides the index to use
for env->banked_r13[] and env->banked_cpsr[].

All the points in the code that were using bank_number()
to index into env->banked_r14[] are updated for consintency:
 * switch_mode() -- this is the only place where we fix
   an actual bug
 * aarch64_sync_32_to_64() and aarch64_sync_64_to_32():
   no behavioural change as we already special-cased Hyp R14
 * kvm32.c: no behavioural change since the guest can't ever
   be in Hyp mode, but conceptually the right thing to do
 * msr_banked()/mrs_banked(): we can never get to the case
   that accesses banked_r14[] with tgtmode == ARM_CPU_MODE_HYP,
   so no behavioural change

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-id: 20181109173553.22341-2-peter.maydell@linaro.org
This commit is contained in:
Peter Maydell 2018-11-13 10:47:59 +00:00
parent 89430fc6f8
commit 593cfa2b63
4 changed files with 35 additions and 18 deletions
Download patch file Download diff file Expand all files Collapse all files

16
target/arm/internals.h
View file

@ -145,6 +145,22 @@ static inline int bank_number(int mode)
g_assert_not_reached();
}
/**
* r14_bank_number: Map CPU mode onto register bank for r14
*
* Given an AArch32 CPU mode, return the index into the saved register
* banks to use for the R14 (LR) in that mode. This is the same as
* bank_number(), except for the special case of Hyp mode, where
* R14 is shared with USR and SYS, unlike its R13 and SPSR.
* This should be used as the index into env->banked_r14[], and
* bank_number() used for the index into env->banked_r13[] and
* env->banked_spsr[].
*/
static inline int r14_bank_number(int mode)
{
return (mode == ARM_CPU_MODE_HYP) ? BANK_USRSYS : bank_number(mode);
}
void arm_cpu_register_gdb_regs_for_features(ARMCPU *cpu);
void arm_translate_init(void);