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author | Stefano Stabellini <stefano.stabellini@eu.citrix.com> | 2012-03-13 16:04:05 +0000 |
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committer | Stefano Stabellini <stefano.stabellini@eu.citrix.com> | 2012-03-13 16:04:05 +0000 |
commit | 40f20c4bfcd5d25c90f9419250ca8a229bf4c1e5 (patch) | |
tree | 874f1e9f8b886f87c0100149330199ff27c84a73 /xen | |
parent | bf321201462ccf313c716e8067ed6795f405182d (diff) | |
download | xen-40f20c4bfcd5d25c90f9419250ca8a229bf4c1e5.tar.gz xen-40f20c4bfcd5d25c90f9419250ca8a229bf4c1e5.tar.bz2 xen-40f20c4bfcd5d25c90f9419250ca8a229bf4c1e5.zip |
arm: use r12 to pass the hypercall number
** This is a guest visible ABI change which requires an updated guest kernel **
Use r12 to pass the hypercall number and r0-r4 for the hypercall
arguments.
Use the ISS to pass an hypervisor specific tag.
Remove passing unused registers to arm_hypercall_table: we don't have 6
arguments hypercalls and we never use 64 bit values as hypercall
arguments, 64 bit values are only contained within structs passed as
arguments.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
[ use #ifndef NDEBUG, fix coding style, expand calling convention comment
slightly and added a big fat note about ABI change - ijc ]
Committed-by: Ian Campbell <ian.campbell@citrix.com>
Diffstat (limited to 'xen')
-rw-r--r-- | xen/arch/arm/traps.c | 33 | ||||
-rw-r--r-- | xen/include/public/arch-arm.h | 23 |
2 files changed, 45 insertions, 11 deletions
diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c index 395d0af34e..acf8f6e2fc 100644 --- a/xen/arch/arm/traps.c +++ b/xen/arch/arm/traps.c @@ -367,7 +367,6 @@ unsigned long do_arch_0(unsigned int cmd, unsigned long long value) } typedef unsigned long arm_hypercall_t( - unsigned int, unsigned int, unsigned int, unsigned int, unsigned int, unsigned int, unsigned int, unsigned int, unsigned int, unsigned int); #define HYPERCALL(x) \ @@ -407,18 +406,30 @@ static void do_debug_trap(struct cpu_user_regs *regs, unsigned int code) static void do_trap_hypercall(struct cpu_user_regs *regs, unsigned long iss) { + arm_hypercall_t *call = NULL; local_irq_enable(); - regs->r0 = arm_hypercall_table[iss](regs->r0, - regs->r1, - regs->r2, - regs->r3, - regs->r4, - regs->r5, - regs->r6, - regs->r7, - regs->r8, - regs->r9); + if ( iss != XEN_HYPERCALL_TAG ) + { + printk("%s %d: received an alien hypercall iss=%lx\n", __func__ , + __LINE__ , iss); + regs->r0 = -EINVAL; + return; + } + + call = arm_hypercall_table[regs->r12]; + if ( call == NULL ) + { + regs->r0 = -ENOSYS; + return; + } + + regs->r0 = call(regs->r0, regs->r1, regs->r2, regs->r3, regs->r4); + +#ifndef NDEBUG + /* clobber registers */ + regs->r1 = regs->r2 = regs->r3 = regs->r4 = regs->r12 = 0xDEADBEEF; +#endif } static void do_cp15_32(struct cpu_user_regs *regs, diff --git a/xen/include/public/arch-arm.h b/xen/include/public/arch-arm.h index edb78b488b..1b1bcf3235 100644 --- a/xen/include/public/arch-arm.h +++ b/xen/include/public/arch-arm.h @@ -27,6 +27,29 @@ #ifndef __XEN_PUBLIC_ARCH_ARM_H__ #define __XEN_PUBLIC_ARCH_ARM_H__ +/* hypercall calling convention + * ---------------------------- + * + * A hypercall is issued using the ARM HVC instruction. + * + * A hypercall can take up to 5 arguments. These are passed in + * registers, the first argument in r0, the second argument in r1, the + * third in r2, the forth in r3 and the fifth in r4. + * + * The hypercall number is passed in r12. + * + * The HVC ISS must contain a Xen specific TAG: XEN_HYPERCALL_TAG. + * + * The return value is in r0. + * + * The hypercall will always clobber r0, r1, r2, r3, r4 and r12, + * regardless of how many arguments the particular hypercall takes. + * + */ + +#define XEN_HYPERCALL_TAG 0XEA1 + + #ifndef __ASSEMBLY__ #define ___DEFINE_XEN_GUEST_HANDLE(name, type) \ typedef struct { type *p; } __guest_handle_ ## name |